High performance catalysts for carbometallic oil conversion and their manufacturing and use

ABSTRACT

A catalyst nominally containing zeolite, preferably HY zeolite and/or ultrastable HY zeolite, clay, alumina and an acidic silica-alumina co-gel matrix. The zeolite is preferably partially exchanged with high La/Ce ratio solution in a wetting step, and rare earths are precipitated onto the matrix. The catalyst has high metals tolerance and is capable of cracking heavy reduced crude oils, producing higher LCO/slurry oil ratio.

CROSS REFERENCES TO RELATED APPLICATIONS

The present invention relates to the general field of the followingpatent applications: U.S. Ser. No. 532,252, filed Sept. 15, 1983; U.S.Ser. No. 263,391, filed May 13, 1981, which has issued as U.S. Pat. No.4,407,714; U.S, Ser. No. 507,864, filed June 27, 1983; U.S. Ser. No.318,185, filed May 20, 1981, now abandoned; U.S. Ser. No. 263,398, filedMay 13, 1981 which has issued as U.S. Pat. No. 4,374,019; U.S. Ser. No.413,870, filed Sept. 2, 1982; U.S. Ser. No. 296,679, filed Aug. 27,1981; and U.S. Ser. No. 252,967, filed Apr. 10, 1981, now abandoned. Thetechniques of U.S. Ser. No. 228,393, filed Jan. 26, 1981 (multi-stageregeneration) are also applicable to the invention.

BACKGROUND OF THE INVENTION

(I) Field of the Invention

The present invention relates to the general field of catalysts andprocesses applicable to the conversion of hydrocarbons particularly theconversion of heavy oils contaminated with substantial amounts of metalsand carbon e.g. reduced crudes.

In the evolution of catalytic cracking, the process has graduallyevolved from a hardware standpoint, until it has reached its presentstate of develoment in fluid catalytic cracking of vacuum gas oils.However, some of the considerable advances in hardware have come aboutas a result of the introduction of new and very unique catalysts (namelythe introduction of the zeolite catalyst which enabled the hardware toevolve to riser cracking with very short contact times).

Likewise, in reduced crude conversion of carbometallic oils, a processhas been developed (Myers, Busch, U.S. Pat. No. 4,299,687) with all itsattendant hardware, designed to facilitate the conversion of these highboiling residues into high octane gasoline with low capital investmentand operating costs. However, it was fully appreciated that in order torealize the tremendous potential volume conversion to liquidtransportation products existant in reduced crude, that highly selectivecatalysts would be required.

As pointed out in our letter to the editor of Science (reference 1980)it has been the intent of research to evolve a catalyst which could, inthis process, utilize all the hydrogen and carbon in a most efficientmanner. It was pointed out in that article that there is sufficienthydrogen available so as to convert all of reduced crude into acombination of toluene and pentenes in greater than 100 volume % yield,and with high octanes over 100, and that the only limiting factor toachieving such a result was the catalyst.

With that realization in mind, the inventors of this new catalyst havesought by very intensive research means to create a catalyst which, whenharnessed with the unique features of the reduced crude conversionprocess, serve to obtain a yield of liquid transportation productspreviously not considered possible. In order to achieve this objective,it has been necessary that all aspects of catalytic conversion beconsidered and that all those properties required to reduce coke andhydrogen production, increase gasoline and light cycle oil yield,immobilize or reduce the effect of vanadia, inhibit the adverse effectsof nickel, facilitate cracking in the presence of high molecular weightmolecules so as to achieve cracking in the sieve, and also to operate inthe presence of high molecular weight basic nitrogen compounds whichtend to neutralize acid sites be optimized. In our invention, all ofthese features were concentrated on, and optimized, so as to produce ametal resistant, high performance catalyst to be harnessed with this newreduced crude conversion process.

(II) Description of the Prior Art

Because of the economic importance of the field of the presentinvention, a number of patent applications and technical publicationshave been addressed to the search for catalysts which will provide themost valuable product distribution while maintaining their activity andwhich are produceable at reasonable cost. The Assignee of the presentapplication has itself directed substantial activity to the field ofheavy oil conversion and its patents and pending applications include:

U.S. Pat. No. 4,341,624 to George D. Myers filed 11/14/79.

U.S. Pat. No. 4,347,122 to George D. Myers et al filed 11/14/79.

U.S. Pat. No. 4,299,687 to George D. Myers et al filed 11/14/79.

U.S. Pat. No. 4,354,923 to George D. Myers et al filed 11/14/79.

U.S. Pat. No. 4,332,673 to George D. Myers et al filed 11/14/79.

U.S. Ser. No. 06/296,679 to W. P. Hettinger, Jr. et al filed 8/27/81.

U.S. Ser. No. 06/263,391 to W. P. Hettinger, Jr. et al filed 5/13/81.

Filtrol Corporation patents and literature include:

    ______________________________________                                        U.S. Pat. No. 4,058,484                                                                     Alafandi NH.sub.4 - faujasite                                   U.S. Pat. No. 4,085,069                                                                     Alafandi NH.sub.4 - faujasite in a                                                     matrix                                                 U.S. Pat. No. 4,086,187                                                                     Lim      attrition resistant                                                           catalyst                                               U.S. Pat. No. 4,100,108                                                                     Alafandi 2 zeolites in matrix                                   U.S. Pat. No. 4,192,778                                                                     Alafandi RE exchanged faujasite                                 U.S. Pat. No. 4,198,319                                                                     Alafandi faujasite + Si--Al                                                            gel (50-70% SiO.sub.2) +                                                      clay                                                   U.S. Pat. No. 4,206,085                                                                     Lim      faujasite + Al.sub.2 O.sub.3 +                                                silica sol                                             U.S. Pat. No. 4,215,016                                                                     Alafandi NaY + cations                                                                 exchange at <500° F.                                                   under pressure                                         U.S. Pat. No. 4,234,457                                                                     Alafandi RE exchange of Si--AL                                                         matrix                                                 U.S. Pat. No. 4,252,684                                                                     Alafandi RE exchange of Si--AL                                                         matrix                                                 U.S. Pat. No. 4,224,188                                                                     Alafandi exchange of NaY with                                                          Al ion, then NH.sub.4 ion                              U.S. Pat. No. 4,228,137                                                                     Taylor   produce faujasite by                                                          seeding with clay                                                             from halloysite                                        U.S. Pat. No. 4,237,031                                                                     Alafandi RE exchange of                                                                ammonium Si--Al                                                               matrix under                                                                  temp-pressure                                          U.S. Pat. No. 4,246,138                                                                     Alafandi RE exchange of                                                                ammonium Si--Al                                                               matrix under                                                                  temp-pressure                                          U.S. Pat. No. 4,259,210                                                                     Alafandi RE exchange of                                                                ammonium Si--Al                                                               matrix under                                                                  temp-pressure                                          U.S. Pat. No. 4,142,995                                                                     Alafandi RE faujasite in                                                               Si--Al matrix                                          U.S. Pat. No. 4,253,989                                                                     Lim      REY + Clay + Al.sub.2 O.sub.3 +                                               0.5-3.5% SiO.sub.2                                     U.S. Pat. No. 4,269,815                                                                     Lim      NaY - multiple                                                                exchange with NH.sub.4                                                        under temp-pressure                                    U.S. Pat. No. 4,310,441                                                                     Alafandi large pore Si--Al                                                             from cationic to                                                              anionic Al sources                                                            with 0.6 cc/g PV in                                                           20-600 A range                                         U.S. Pat. No. 4,325,845                                                                     Lim      zeolite in matrix                                                             (clay + silica gel                                                            from Na silicate)                                      U.S. Pat. No. 4,325,847                                                                     Lim      zeolite in matrix                                                             (pseudoboehmite +                                                             alumina gel)                                           U.S. Pat. No. 4,333,857                                                                     Lim      zeolite < 3 microns                                                           in matrix of                                                                  pseudoboehmite,                                                               clay, silica sol                                       ______________________________________                                    

Article

"New Generation of FCC Catalyst", E. J. Demmel and J. C. Lim, APIProceedings, Vol. 58, Pg. 29-32, April 1975, Reprint 04-79.

Mobil Oil Company's patents include:

    ______________________________________                                        U.S. Pat. No. 3,790,471                                                                      Argaver   ZSM-5                                                U.S. Pat. No. 4,088,605                                                                      Rollman   ZSM-5 with an Al.sub.2 O.sub.3                                                free outer shell                                     U.S. Pat. No. 4,148,713                                                                      Rollman   ZSM-5 with an Al.sub.2 O.sub.3                                                outer shell                                          U.S. Pat. No. 4,203,869                                                                      Rollman   ZSM-5 with an Al.sub.2 O.sub.3                                                free outer shell                                     U.S. Pat. No. 4,199,556                                                                      Plank     ZSM-5 formed with                                                             N--cpds                                              U.S. Pat. No. 4,205,053                                                                      Rollman   ZSM-5 formed with                                                             N--template and N                                                             basic cpd.                                           U.S. Pat. No. 4,139,600                                                                      Rollman   ZSM-5 formed by use                                                           of diamines                                          U.S. Pat. No. 4,151,189                                                                      Rubin     ZSM-5 formed by use                                                           of 2-9 carbon                                                                 containing primary                                                            monoalkylamine                                       U.S. Pat. No. 4,285,922                                                                      Audel     ZSM-5 formed by use                                                           of alkyl ammonium-                                                            N--oxide                                             U.S. Pat. No. 4,100,262                                                                      Pelrine   Cobalt containing                                                             ZSM-5                                                U.S. Pat. No. 4,273,753                                                                      Chang     HZSM-5 type,                                                                  produced through use                                                          of halide or                                                                  oxyhalide to                                                                  dealuminate zeolite                                  U.S. Pat. No. 4,275,047                                                                      Whitton   ZSM-5 produced by                                                             seeding with Nu--1                                                            crystal                                              ______________________________________                                    

Davison Chemical Division of W. R. Grace's patents include:

    ______________________________________                                        U.S. Pat. No. 3,595,611                                                                     McDaniel  PCY zeolite + Al.sub.2 O.sub.3 -                                              thermal                                                                       stabilization                                         U.S. Pat. No. 3,607,043                                                                     McDaniel  PCY zeolite + Al.sub.2 O.sub.3 -                                              thermal                                                                       stabilization                                         U.S. Pat. No. 3,692,665                                                                     McDaniel  PCY zeolite + Al.sub.2 O.sub.3 -                                              thermal                                                                       stabilization                                         U.S. Pat. No. 3,676,368                                                                     Scherzer  REHY zeolite + SiAl                                                           hydrogel + mordenite                                                          or type A                                             U.S. Pat. No. 3,894,940                                                                     Scherzer  REHY zeolite + SiAl                                                           hydrogel + mordenite                                                          or type A                                             U.S. Pat. No. 3,925,195                                                                     Scherzer  REHY zeolite + SiAl                                                           hydrogel + mordenite                                                          or type A                                             U.S. Pat. No. 3,293,192                                                                     Maher     Z14-US                                                U.S. Pat. No. 3,449,070                                                                     McDaniel  Z14-US                                                U.S. Pat. No. 3,867,310                                                                     Elliott   CREY                                                  U.S. Pat. No. 3,957,623                                                                     McDaniel  CREY                                                  U.S. Pat. No. 3,650,988                                                                     Magee     Similar to Super D                                    U.S. Pat. No. 3,986,946                                                                     Baker     Zeolite--SiO.sub.2 --MgO--F                           U.S. Pat. No. 4,107,088                                                                     Elliott   addition of Ti or Zr                                                          to matrix                                             U.S. Pat. No. 4,126,579                                                                     Flaherty  silica gel - zeolite                                                          slurry (new spray                                                             nozzle design)                                        U.S. Pat. No. 4,218,307                                                                     McDaniel  USY (NaY + RE →                                                        heat → acid                                                            treat) Si/Al                                          U.S. Pat. No. 4,144,194                                                                     Guidry    faujasite + silicate                                                          from zeolite                                                                  preparation                                           U.S. Pat. No. 4,164,551                                                                     Elliott   Y zeolite                                                                     preparation -                                                                 silicate solution                                                             for matrix                                            U.S. Pat. No. 4,166,099                                                                     McDaniel  Y zeolite                                                                     preparation - seeded                                                          with zeolite <0.1                                                             microns                                               U.S. Pat. No. 4,175,059                                                                     Edwards   K faujasite -                                                                 platelet type                                                                 shape                                                 U.S. Pat. No. 4,178,352                                                                     Vaughn    Y zeolite                                                                     preparation                                           U.S. Pat. No. 4,247,420                                                                     Doumoulin Si--Al cogel +                                                                zeolite                                               U.S. Pat. No. 4,332,699                                                                     Nozemack  Al.sub.2 O.sub.3 precipitated                                                 onto a zeolite                                        U.S. Pat. No. 4,333,859                                                                     Vaughn    CSZ-3 Co-containing                                                           zeolite                                               U.S. Pat. No. 4,340,573                                                                     Vaughn    Y zeolite                                                                     preparation -                                                                 zeolite from prep as                                                          seeds                                                 U.S. Pat. No. 3,402,996                                                                     Maher     NaY + RE  →                                                            Calcination -                                                                 multi-step exchange                                                           and calcination                                                               yielding Z14-HS &                                                             Z14-US                                                ______________________________________                                    

Patents of others include:

    ______________________________________                                        U.S. Pat. No. 4,215,015                                                                     Tu (UOP)    zeolite in a Si--Al                                                           matrix plus polymer;                                                          the polymer is                                                                burned out leaving a                                                          pore structure in                                                             the 100-300 A range;                                                          Ti can be added to                                                            matrix.                                             U.S. Pat. No. 4,239,615                                                                     Tu (UOP)    zeolite in a Si--Al                                                           matrix plus polymer;                                                          the polymer is                                                                burned out leaving a                                                          pore structure in                                                             the 100-300 A range;                                                          Ti can be added to                                                            matrix.                                             U.S. Pat. No. 4,299,733                                                                     Tu (UOP)    zeolite in a Si--Al                                                           matrix plus polymer;                                                          the polymer is                                                                burned out leaving a                                                          pore structure in                                                             the 100-300 A range;                                                          Ti can be added to                                                            matrix.                                             U.S. Pat. No. 4,333,821                                                                     Tu (UOP)    zeolite in a Si--Al                                                           matrix plus polymer;                                                          the polymer is                                                                burned out leaving a                                                          pore structure in                                                             the 100-300 A range;                                                          Ti can be added to                                                            matrix.                                             U.S. Pat. No. 4,263,174                                                                     Tu (UOP)    spray dried catalyst +                                                        RE salt solution;                                                             then dried but not                                                            washed; this gives                                                            RE by exchange and                                                            impregnation                                        U.S. Pat. No. 4,269,813                                                                     Klotz       Borosilicate                                                      (Amoco)     zeolite                                             U.S. Pat. No. 4,285,919                                                                     Klotz       Borosilicate                                                      (Amoco)     zeolite                                             U.S. Pat. No. 4,327,236                                                                     Klotz       Borosilicate                                                      (Amoco)     zeolite                                             U.S. Pat. No. 4,036,739                                                                     Ward (Union)                                                                              NH.sub.4 exchange - steam                                                     treat - NH.sub.4 exchange                                                     (<1% Na.sub.2 O) in                                                           zeolite                                             U.S. Pat. No. 4,239,654                                                                     Gladrow     USY + ZSM in a                                                    (Exxon)     matrix                                              U.S. Pat. No. 4,308,129                                                                     Gladrow     USY (5-40%) +                                                     (Exxon)     5-40% Al.sub.2 O).sub.3 +                                                     40-90% Al.sub.2 O.sub.3                             U.S. Pat. No. 4,147,613                                                                     Gladrow     3-16% zeolite in                                                  (Exxon)     matrix of SiO.sub.2 --                                                        Al.sub.2 O.sub.3 --ZrO.sub.2 +                                                15-40% Al.sub.2 O.sub.3. This                                                 produces a catalyst                                                           having at least 0.4                                                           cc/g of its pore                                                              volume in pores                                                               >90° A.                                      U.S. Pat. No. 4,151,119                                                                     Gladrow     3-16% zeolite in                                                  (Exxon)     matrix of SiO.sub.2 --                                                        Al.sub.2 O.sub.3 --ZrO.sub.2 +                                                15-40% Al.sub.2 O.sub.3. This                                                 produces a catalyst                                                           having at least 0.4                                                           cc/g of its pore                                                              volume in pores                                                               >90° A.                                      U.S. Pat. No. 4,283,309                                                                     Gladrow     3-16% zeolite in                                                  (Exxon)     matrix of SiO.sub.2 --                                                        Al.sub.2 O.sub.3 --ZrO.sub.2 +                                                15-40% Al.sub.2 O.sub.3. This                                                 produces a catalyst                                                           having at least 0.4                                                           cc/g of its pore                                                              volume in pores                                                               >90° A.                                      U.S. Pat. No. 4,292,169                                                                     Gladrow     3-16% zeolite in                                                  (Exxon)     matrix of SiO.sub.2 --                                                        Al.sub.2 O.sub.3 --ZrO.sub.2 +                                                15-40% Al.sub.2 O.sub.3. This                                                 produces a catalyst                                                           having at least 0.4                                                           cc/g of its pore                                                              volume in pores                                                               >90° A.                                      U.S. Pat. No. 3,442,795                                                                     Kerr (Mobil)                                                                              Stabilization of NH.sub.4                                                     to yield a high                                                               Si/Al ratio zeolite                                 U.S. Pat. No. 3,493,519                                                                     Kerr (Mobil)                                                                              Stabilization with                                                            NH.sub.4 to yield a high                                                      Si/Al ratio zeolite                                 U.S. Pat. No. 3,553,104                                                                     Stover      A matrix of a pore                                                (Mobil)     volume > = 0.6 cc/g                                 U.S. Pat. No. 4,219,406                                                                     Kuehl       Si--Al hydrogel +                                                 (Mobil)     zeolite is spray                                                              dried, exchanged with                                                         NH.sub.4 --Al--RE ions                                                        then washed, dried                                                            and impregnated with                                                          RE's                                                U.S. Pat. No. 4,219,446                                                                     Kuehl       Si--Al hydrogel +                                                 (Mobil)     zeolite is spray                                                              dried exchanged with                                                          NH.sub.4 --Al--Re ions                                                        then washed, dried                                                            and impregnated with                                                          RE's                                                U.S. Pat. No. 4,326,993                                                                     Chester     1-75% zeolite +                                                   (Mobil)     colloidal SiO.sub.2 +                                                         colloidal Al.sub.2 O.sub.3 +                                                  clay and 40% of pore                                                          vol. in 30-300A                                                               sized pores                                         USSN 195848   10Oct1980   (French Demande                                                   Gladrow     2,491,777; 97CA                                                               58340e) ultra                                                                 stable Y-type                                                                 zeolite 20%, porous                                                           Al.sub.2 O.sub.3 particles 20%,                                               silica-alumina gel                                                            matrix 60% and                                                                uniformally                                                                   distributed rare                                                              earth oxides                                                                  0.01-0.08% used to                                                            crack gas oil (not                                                            heavy oil) to                                                                 gasoline with                                                                 conversion of 73.2%                                 ______________________________________                                    

Procesing of the higher boiling fractions of crude oil in a fluidcatalytic cracking unit has been practiced for many decades. Theexpertise developed has been along the lines of an easily vaporizablefeed such as vacuum gas oil (VGO) containing very little contaminants.Thus, for many years, those skilled in the art have been concerned withdeveloping catalysts having improved activity, improved selectivity,improved stability, and metal tolerance related to mild operations. Bymild operations we refer to (1) feed contaminants being low (ConradsonCarbon below 2 WT %, Ni+V contents of the feed below 5 ppm, endpoint offeedstock at 566° C. (1050° F.) (thus 100% vaporizable under processconditions), (2) mild process conditions (regenerator temperatures below704° C. (1300° F.), no need to employ excessive amounts of steam andwater as lift gas and coolants to maintain unit heat balance); this isalso due to coke make, (3) catalyst properties with low porosity toreduce carryover of gases and hydrocarbon to regenerator, (4) catalyststability--metal tolerance of matrix and zeolite not critical due to lowmetal deposition, and low regenerator temperature. The bad metal actoris nickel which is controlled by antimony addition.

The following table illustrates the changes in process severity andcatalyst needs with feedstock change:

                                      TABLE I                                     __________________________________________________________________________                VGO   VGO + RESID                                                                            REDUCED CRUDE                                      __________________________________________________________________________    FEEDSTOCK                                                                     PROPERTIES                                                                    VGO-%        100  95       --                                                 FEEDSTOCK                                                                     PROPERTIES                                                                    Heavy Resid-%                                                                             --    5        --                                                 Reduced Crude-%                                                                           --    --       100                                                Feed Endpoint °F.                                                                  1050  1300     up to 1800                                         Conradson Carbon                                                                          0.2   1-2       4-12                                              Metals ppm  0.2   5         10-200                                            PROCESS                                                                       CONDITIONS                                                                    Reactor Temp. °F.                                                                   940   940-960  945-1050                                          Regenerator Temp °F.                                                               1150-1200                                                                           1200-1300                                                                              1300-1400                                          Steam-H.sub.2 O addition                                                                  <1%    1-2%      5-20%                                            wt. % feed                                                                    CATALYST                                                                      PROPERTIES                                                                    Metals on Catalyst ppm                                                                     500-1000                                                                           1000-3000                                                                                3000-20,000                                      Carbon on Catalyst -                                                                      4-5   6-8       8-16                                              wt. % feed                                                                    Effect of Ni                                                                              H.sub.2 --coke                                                                      H.sub.2 --coke                                                                         H.sub.2 --coke                                     Effect of V nil   nil      H.sub.2 --coke and zeolite-                                                   matrix                                                                        destruction                                        Pore size-Angstroms                                                                       varied                                                                              varied   100-1000Å + larger                             Pore Volume cc/gm                                                                         0.2-0.3                                                                             0.3      0.4-0.5 or more                                    Acidity in the Matrix                                                                     No    No       Yes                                                Metal Passivation Ni                                                                      Ni w/Sb                                                                             Ni w/Sb  Ni w/Sb, + La + Ti + Al.sub.2 O.sub.3              Metal Passivation V                                                                       V-nil V-nil    V w/ La + Ti + Al.sub.2 O.sub.3                    Effect of Basic Nitrogen                                                                  nil   nil      Great                                              __________________________________________________________________________

To one skilled in the art the extension of known catalyst propertieswhen processing of VGO to processing VGO+ small amounts of residrequires only a small adjustment or fine tuning of VGO catalystsproperties to take care of the changes in process and feedstocks, e.g.,small incresaes in metal content, Conradson Carbon, regeneratortemperatures, and feedstock. This is demonstrated by the above patentliterature in which individual properties have been varied to change oraccent a single catalyst property or process variable.

However, in none of the attached references is the total concept ofcatalyst development for reduced crude processing anticipated byadopting zeolite type, cracking activity balanced by acid site strength(Bronsted and Lewis acids); partial rare earth addition; rare earthtype; matrix properties such as activity, acidity, and proper matrixporosity; metal control through acidic site exchange; passivation andimmobilization of nickel and vanadium; sieve accessibility; absorptionand vaporization of heavy hydrocarbons; resistance to nitrogen poisoningand high sulfur levels; able to function at high process temperaturesthrough selective cracking; thermal-hydrothermal stability of matrix andzeolites; low coke formation through choice of zeolite system andconcentration in matrix; and still maintain a cost effective catalystallowing resonable addition rates. Thus, the processing of reduced crudein a fluidized process employing the catalyst ofthis invention is asignificant advance in catalyst development because it requires theutilization and the balance in a most highly developed form of theaforementioned properties.

The catalyst of this invention is also such an advance in which a selectzeolite, having excellent thermal-hydrothermal stability throughselected properties of silica-alumina ratio (unit cell constant), isonly partially rare earth exchanged so as to enjoy a balance of acidityor activity via Bronsted and Lewis acid sites. This balance is criticalto product distribution and to maintaining the optimum amount of acidsites or cracking sites in the unit to avoid overcracking and increasedcoke production. The amount of acidity present in the matrix is alsobalanced with zeolite acidity so as to maintain high selectivity togasoline and avoid overcracking and coke deposition. Thus, there is abalance between zeolite properties and zeolite concentration in thematrix and the properties of the matrix itself to attain theaforementioned selectivities (gasoline-coke). In addition, the rareearth utilized is lanthanum rich so that a higher hydrothermal stablezeolite, also more resistant to vanadia, is obtained with better metaltolerance.

The matrix of the catalyst of this invention is as vital a part of thetotal catalyst as is the zeolite. The matrix must have the followingproperties: proper and selective pore size distribution, large porevolume, metal tolerance and metal immobilization properties, in additionto the typical properties of particle size distribution, density andgood attrition index. Most importantly, it is necessary that the matrixalso possess a considerable amount of, and stable acidity, in order toachieve molecular size reduction which permits a molecule entrance intothe highly active zeolite. A critical balance between sieve and matrixacidity and acid strength as well as matrix resistance to thermal,hydro-thermal and metals deactivation must also be achieved so thatsieve and matrix acidity remain coupled and balanced as the catalystages.

The porosity (pore size-volume) of a catalyst is critical whenprocessing reduced crudes. Since the catalyst of this invention requiresan acidic matrix to crack the higher boiling components above 540° C.(1000° F.) to lower boiling fragments to ensure total vaporization ofthe feed, and to permit access of larger molecules to sieve pores, aspecific pore volume and pore size distribution is required to ensurethat all liquids and vapors can be absorbed and transported to thezeolite and all products transported away from the zeolite withoutencountering diffusional problems. Furthermore, a large pore volume isrequired to accommodate liquids depositing in the pores, and coke andmetals depositing in the pores without affecting transport (diffusionalproblems of feed liquid and vapors to and product vapors from thezeolite particle.

Finally, an additional property is incorporated into the matrix in theform of metal passivators, immobilizers, and/or sacrificial sieves ortraps. This involves the incorporation of such as alumina, titania orzirconia to immobilize nickel and vanadia, the precipitation oflanthanum into the matrix to immobilize vanadia, or the addition of lessexpensive sieves to serve as sacrificial sieves in order to spare theperformance of the catalytic zeolite. It should be noted that theimpregnation or exchange of La into the matrix is much less effectivefor Ni-V immobilization. It is preferred that the La be precipitatedonto the matrix.

It will be noted that the multi-concepts and combinations incorporatedinto the development of the catalyst of this invention for reduced crudeprocessing is not readily available from the literature and requireddevelopment of the concepts singularly and then on a multi-compositionalbasis.

Despite all of the work evidence by the above patents, and by manyothers in this general field, the prior investigators have not combinedthe selected reactivity and physical properties of zeolites,silica-alumina gels, clays, aluminas, rare earths, and other additivesto achieve the low coke, low H₂, high octane, high activity, highgasoline selectivity, low slurry oil, metals tolerant and high thermaland hydrothermal stability of the catalysts described in thisapplication. Prior commercial catalyst produce undesirable levels ofslurry oil or produce too much catalytic coke.

Stability of prior catalysts, especially when loaded with metals such asvanadia at higher regenerator temperatures has also been a seriousproblem. The lack of metal poisoning resistance or prior catalyst has,over the past 40 years, been perhaps the single most difficult problemand barrier to the production of transportation fuels from residualoils.

SUMMARY OF THE INVENTION

The process for catalytic cracking of vacuum gas oils has graduallyevolved over a period of many years from a hardware stand point to itspresent state of highly sophisticated development, hardly recognizablewith those early units. However, some of the considerable advances inhardware have come about as the result of the introduction of new andvery unique and highly active catalysts (namely the zeolites) causingthe development of riser cracking with very short contact times.

Similarly, with regard to reduced crude conversion of carbo metallicoils, after some similar 40 years of frustration, a process has now beendeveloped (Myers, Busch U.S. Pat. No. 4,249,687) with all its attendanthardware, designed to facilitate the conversion of these high boilingresidues into high octane gasoline with low capital investment andoperating costs, and in the absence of hydrogen pretreatment. However,it was fully appreciated, even in this case, that in order to furtherrealize or achieve the full and tremendous potential volume of liquidtransportation products inherent in the catalytic conversion of reducedcrude, that new and highly improved catalysts would be most desirable.

As previously pointed out in a letter to the editor of Science (1980) iswas stated that it was the intent of research to evolve a catalyst whichcould, in this process, utilize as much as possible all the hydrogen andcarbon present in the feed stock in a most efficient manner. In thisregard, it was pointed out that with an ideal catalyst, there issufficient hydrogen available in reduced crude so as to convert all thecarbon and hydrogen into a combination of toluene and pentenes, involumes over 100% yeild, and with octane numbers over 100, and that theonly limiting factor to achieving this result is the catalyst, not thehydrogen/carbon balance.

With that realization in mind, the inventors of this new catalyst havesought by very intensive research means to create a catalyst which, whenharnessed with the unique features of the reduced crude conversionprocess, would serve to achieve a yeild of liquid transportationproducts previously not considered possible and within affordablecatalyst costs. In order to achieve this objective, it has beennecessary that all desirable and required properties of a catalyst betuned to this goal. As a result, the catalyst described here, whenoperating on this very low quality feedstock, is still able to:

reduce and minimize cake and hydrogen production,

maximize gasoline and light cycle oil yeild,

immobilize or reduce the effect of vanadia,

inhibit or reduce the adverse effect of nickel,

facilitate cracking in the presence of high molecular weight moleculesso as to achieve cracking in the sieve,

operate in the presence of high molecular weight basic nitrogencompounds which tend to neutralize acid sites,

operate in the presence of large coking molecules such as asphaltenes,without allowing these macro molecules to block access of smallermolecules to catalyst sites,

be economically acceptable.

In this catalyst, all of these features were focused on and optimized soas to produce a high performance, coordinated efficient catalyst, to beharnessed with an equally new reduced crude conversion process in orderto further optimize yield.

(I) General Statement of the Invention

According to the present invention, catalysts are prepared which arecapable of catalytically cracking heavy reduced crude feeds in a processgenerally according to the parameters described in the aforementionedU.S. Pat. No. 4,322,673. Acidity is provided in the matrix to betterconvert larger molecules to smaller high boiling hydrocarbon moleculesable to vaporize and enter the molecular sieves, so as to producemolecules boiling in the 38° to 343° C. (100° to 650° F.) boiling rangee.g. C₅ -C₁₅ paraffins, olefins and aromatics. This range is thetransportation fuel range and the effect of the present catalyst andrelated process is to provide a substantial increase in the amount oftransportation fuels and substantially reduce the yield of residualfuels or asphalt, which are derived from a barrel of crude oil as wellas permitting the conversion of otherwise distressed hydrocarbonfeedstocks into valuable transportation fuels.

The catalyst of the present invention preferably comprise zeolites e.g.HY-type molecular sieves, clays e.g. kaolins and a substantial portionof silica-alumina gels. Preferably the catalysts are partially promotedby several means with a high ratio of lanthanum (La) to cerium (Ce)solution. The catalysts of the invention, when combined with the optimumprocess conditions for processing heavy oil provide the followingbenefits:

A. low catalytic coke production;

B. high light catalytic cycle oil (LCO) to slurry oil (Slurry) ratio inproducts;

C. excellent resistance to metal contamination and poisoning;

D. excellent cracking activity in the presence of high metals containingfeedstocks;

E. stability under high temperatures permitting severe regenerationconditions to remove the high amounts of carbon laid down by residualoils;

F. high gasoline selectivity and production;

G. low slurry production;

H. high octane gasoline;

I. good resistance in terms of catalytic cracking of high basic nitrogencontaining feedstocks;

J. high activity while exposed to large asphaltene molecules,

K. is acceptably low in cost.

(2) Utility of the Invention

The invention is useful in converting low valued distress oils and crudeoils into high valued transportation fuels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. I is a plot showing conversion of reduced crude to products havingboiling points less than 221° C. (430° F.) (in volume percent) versusthe LCO/Slurry (volume) ratio for certain known catalysts and forcatalysts produced according to the present invention.

FIG. II is a plot of gasoline selectivity versus the afore mentionedvolume percent conversion to C₅ -430° F. products.

FIG. III is a plot of the conversion to coke versus the volume percentconversion to C₅ -430° F. products.

FIG. IV is a plot of gasoline (C₅ to below 430° F.) yield (volume %)versus C₅ -430° F. products conversion.

FIG. V is a plot of the conversion to volume % light catalytic cycle oil(430°-630° F.) versus C₅ -430° F. products.

FIG. VI is a plot of the conversion to slurry oil (heavy catalytic cycleoil, 630+° F.) products.

FIG. VII is a schematic diagram of a preferred catalyst of theinvention.

FIG. VIII is a flow diagram of one method of preparation of the catalystof Example 1.

FIG. IX is a plot of gasoline yield (C₅ +-430° F. product) versuscatalyst ratio pore volume (cc/g).

FIG. X is a plot of catalyst activity versus rare earth content ofzeolite.

FIG. XI is a plot of yield of products (gasoline, gas, coke) versus rareearth content of zeolite.

FIG. XII is a plot of catalyst versus method of lanthanum addition tocatalyst.

FIG. XIII is a plot of catalyst activity versus steaming temperaturecomparing the catalyst of this invention to conventionally availablecatalysts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(I): As mentioned above, the feed for the present invention can be crudeoil but, for the full economic realization of the capabilities of theinvention, the feed material will generally be low valued refractorycrudes or portions of crude oils which are especially high in carbon andmetals.

Feed materials particularly useful with the invention comprise but arenot limited to: reduced crude oil from e.g. West Texas, Illinois,Kentucky, Kansas light, medium and heavy Dubai, light, medium and heavyArabian, Quatar, Mayan, Isthmus, Nigerian, Venezuelean, and otherresidual oils, other reduced crudes, vacuum tower bottoms, slurry oils,tar sands, asphalts, bitumens, shale oils, heavy resids, deasphalted gasoil, coker gas oil and gas oil from Engelhard's "ART" demetalizingcontractors, and/or heavy oil hydrogen treating process products.

CARBO-METALLIC OIL CONVERTER FEED

The present invention provides a process for the continuous catalyticconversion of a wide variety of carbo-metallic oils to lower molecularweight products, while maximizing production of highly valuable liquidproducts, and making it possible, if desired, to avoid vacuumdistillation and other expensive treatments such as hydrotreating. Theterm "oils", includes not only those predominantly hydrocarboncompositions which are liquid at room temperature, i.e., 20° C. (68°F.), but also those predominantly hydrocarbon compositions which areasphalts or tars at ambient temperature but liquify when heated totemperatures in the range of up to about 427° C. (800° F.). Theinvention is applicable to carbo-metallic oils, whether of petroleumorigin or not. For example, provided they have the requisite boilingrange, carbon residue on pyrolysis and heavy metals content, theinvention may be applied to the processing of such widely diversematerials as heavy bottoms from crude oil, heavy bitumen crude oil,those crude oils known as "heavy crude" which approximate the propertiesof reduced crude, shale oil, tar sand extract, products from coalliquification and solvated coal, atmospheric and vacuum reduced crude,extracts and/or bottoms (raffinate) from solvent de-asphalting, aromaticextract from lube oil refining, tar bottoms, heavy cycle oil, slop oil,other refinery waste streams and mixtures of the foregoing. Suchmixtures can for instance be prepared by mixing available hydrocarbonfractions, including oils, tars, pitches and the like. Also, powderedcoal may be suspended in the carbo-metallic oil. Persons skilled in theart are aware of techniques for demetalation of carbo-metallic oils, anddemetalated oils may be converted using the invention; but it is anadvantage of the invention that it can employ as feedstockcarbo-metallic oils that have had no prior demetalation treatment.Likewise, the invention can be applied to hydrotreated feedstocks; butit is an advantage of the invention that it can successfully convertcarbo-metallic oils which have had substantially no priorhydrotreatment. However, the preferred application of the process is toreduced crude, i.e., that fraction of crude oil boiling at and above343° C. (650° F.), alone or in admixture with virgin gas oils. While theuse of material that has been subjected to prior vacuum distillation isnot excluded, it is an advantage of the invention that it cansatisfactorily process material which has had no prior vacuumdistillation, thus saving on capital investment and operating costs ascompared to conventional FCC processes that require a vacuumdistillation unit.

In accordance with the invention one provides a carbo-metallic oilfeedstock, at least about 70%, more preferably at least about 85% andstill more preferably about 100% (by volume) of which boils at and aboveabout 343° C. (650° F.). All boiling temperatues herein are based onstandard atmospheric pressure conditions. In carbo-metallic oil partlyor wholly composed of material which boils at and above about 343° C.(650° F.), such material is referred to herein as 343° C.+ (650° F.+)material; and 343° C.+ (650° F.+) material which is part of or has beenseparated from an oil containing components boiling above and below 343°C. (650° F.) may be referred to as a 343° C.+ (650° F.+) fraction. Butthe terms "boils above" and "343° C.+" ("650° F.+") are not intended toimply that all of the material characterized by said terms will have thecapability of boiling. The carbo-metallic oils contemplated by theinvention may contain material which may not boil under any conditions;for example, certain asphalts and asphaltenes may crack thermally duringdistillation, apparently without boiling. Thus, for example, when it issaid that the feed comprises at least about 70% by volume of materialwhich boils above about 343° C. (650° F.), it should be understood thatthe 70% in question may include some material which will not boil orvolatilize at any temperature. These non-boilable materials, whenpresent, may frequently or for the most part be concentrated in portionsof the feed which do not boil below about 538° C., 552° C. or higher(about 1000° F., 1025° F. or higher). Thus, when it is said that atleast about 10%, more preferably about 15% and still more preferably atleast about 20% by (by volume) of the 343° C.+ (650° F.+) fraction willnot boil below about 538° C. or 522° C. (1000° F. or 1025° F.), itshould be understood that all or any part of the material not boilingbelow about 538° C. (1000° F.) or 552° C. (1025° F.), may or may not bevotlatile at and above the indicated temperatures.

Preferably, the comtemplated feeds, or at least the 343° C.+ (650° F.+)material therein, have a carbon residue on pyrolysis of at least about 2or greater. For example, the Ramsbottom carbon content may be in therange of about 2 to about 12 and most frequently at least about 4. Aparticularly common range is about 4 to about 8. Note that theillustrative VGO in Table 1 has a Ramsbottom carbon residue value of0.38, and that the 343° C. to 552° C. (650° F. to 1025° F.) fractions ofthe various reduced crudes have Ramsbottom carbon values between about0.3 and about 0.5, whereas the various reduced crudes as a whole (650+Total) vary upwards in Ramsbottom carbon value from about 4 to about16.8, and still higher values are contemplated.

Preferably, the feed has an average composition characterized by anatomic hydrogen to carbon ratio in the range of about 1.2 to about 1.9,and more likely about 1.3 to about 1.8

The carbo-metallic feeds employed in accordance with the invention, orat least the 343° C.+ (650° F.+) material therein, may contain at leastabout 4 parts per million of Nickel Equivalents, as defined above, ofwhich at least about 2 parts per million is nickel (as metal, byweight). Carbo-metallic oils within the above range can be prepared frommixtures of two or more oils, some of which do and do not contain thequantities of Nickel Equivalents and nickel set forth above. It shouldalso be noted that the above values for Nickel Equivalents and nickelrepresent time-weighted averages for a substantial period of operationof the conversion unit, such as one month, for example. It should alsobe noted that the heavy metals have in certain circumstances exhibitedsome lessening of poisoning tendency after repeated oxidations andreductions on the catalyst, and the literature describes criteria forestablishing "effective metal" values. For example, see the article byCimbalo, et al, entitled "Deposited Metals Poison FCC Catalyst", Oil andGas Journal, May 15, 1972, pp 112- 122, the contents of which areincorporated herein by reference. If considered necessary or desirable,the contents of Nickel Equivalents and nickel in the carbo-metallic oilsprocessed according to the invention may be expressed in terms of"effective metal" values. Notwithstanding the gradual reduction inpoisoning activity noted by Cimbalo, et al, the regeneration of catalystunder normal FCC regeneration conditions may not, and usually does not,severely impair the dehydrogenation, demethanation and aromaticcondensation activity of heavy metals accumulated on cracking catalyst.

The feed materials for the present invention will generally have boilingranges in the range of from about 221° C. to about 982° C. (about 430°F. to about 1800° F.), more preferably from about 316° C. to about 926°C. (about 600° F. to about 1700° F.), and most preferably from about343° C. to about 815° C. (about 650° F. to about 1500° F.). Particularlypreferred are fractions which contain a substantial portion of 343° C.+(650+° F.) boiling point materials. Such component materials includechemical structures such as paraffins, aromatics and polar compounds,e.g. O-, N-, S-, substituted hydrocarbons and asphaltenes andporphyrins. Dilution with lighter materials will be advantageous withcertain feeds.

The feed materials will generally have Ramsbottom Carbon numbers (ASTMTest D 524) in the range of from about 2 to about 12%, more often fromabout 3 to about 8%, and most often from about 4 to about 8% by wt. ofcarbon. Corresponding Conradson Carbon (ASTM Test D 189) will besomewhat higher and can be correlated by ASTM correlation curves.

Generally the feed materials will contain metals particularly nickel,vanadium, sodium, copper and iron, as well as other metals, e.g.calcium. Total nickel-plus-vanadium will be present in the amount ofabout 5 to 200, more often 10 to 150, and most often (for economicreasons) from about 10 to 100 ppm by weight of total feed.

Less applicable to the present invention, particularly because of theunusual tolerance of the catalysts of the present invention to totalmetals, is the scale of Nickel Equivalents: ##EQU1## as mentioned in theliterature, e.g. at column 2 line 41 of U.S. Pat. No. 4,299,687 to Myersand Busch). Assuming that the amount of vanadium is approximately equalto the amount of nickel, then the feedstocks of the present inventionwill generally be in the range of from about 4 to about 120 ppm ofNickel Equivalents.

Catalyst Composition

Catalysts of the present invention can be characterized as containingpredominantly zeolite, clay and substantial amounts of silica-aluminagel as well as controlled amounts of rare earths and other oxidepromoters and immobilizers. Table II shows the typical physical andchemical properties of the catalyst. Weight percents are based on thetotal weight of the dry finished catalyst unless otherwise noted.

Accordingly, the process may be practiced with catalyst bearingaccumulations of heavy metals which heretofore would have beenconsidered quite intolerable in conventional FCC-VGO operations. Forthese reasons, operation of the process with catalyst bearing heavymetal accumulations in the range of about 3,000 to about 30,000 ppmNickel Equivalents, on the average is contemplated. More specifically,the accumulation may be in the range of about 4,000 to about 30,000 ppmand particularly more than about 5,000 to about 30,000 ppm. Theforegoing ranges are based on parts per million of Nickel Equivalents,in which the metals are expressed as metal, by weight, measured on andbased on regenerated equilibrium catalyst. However, in the event thatcatalyst of adequate activity is available at very low cost, makingfeasible very high rates of catalyst replacement, the carbo-metallic oilcould be converted to lower boiling liquid products with catalystbearing less than 2,000 ppm Nickel Equivalents of heavy metals. Forexample, one might employ equilibrium catalyst from another unit, forexample, an FCC unit which has been used in the cracking of a feed,e.g., vacuum gas oil, having a carbon residue on pyrolysis of less than1 and containing less than about 4 ppm Nickel Equivalents of heavymetals.

In any event, the equilibrium concentration of heavy metals in thecirculating inventory of catalyst can be controlled (includingmaintained or varied as desired or needed) by manipulation of the rateof catalyst addition discussed above. Thus, for example, addition ofcatalyst may be maintained at a rate which will control the heavy metalsaccumulation on the catalyst in one of the ranges set forth above.

In general, it is preferred to employ a catalyst having a relativelyhigh level of cracking activity, providing high levels of conversion andproductivity at low residence times. The conversion capabilities of thecatalyst may be expressed in terms of the conversion produced duringactual operation of the process and/or in terms of conversion producedin standard catalyst activity tests. For example, it is preferred toemploy catalyst which, in the course of extended operation in theprocess, is sufficiently active for sustaining a level of conversion ofat least about 40% and more preferably at least about 50%. In thisconnection, conversion is expressed in liquid volume percent, based onfresh feed. Also, for example, the preferred catalyst may be defined asone which, in its virgin or equilibrium state, exhibits a specifiedactivity expressed as a volume percentage derived by the MAT(micro-activity test). For purposes of the present invention theforegoing percentage is the volume percentage of standard feedstock thatis converted to 221° C. (430° F.) end point gasoline and lighterproducts at 482° C. (900° F.), 16 WHSV (weight hourly space velocity),calculated on the basis of catalyst dried at 593° C. (1100° F.) and 3C/O(catalyst to oil ratio) by the tentative ASTM MAT test developed by ASTMCommittee D-32, using an appropriate standard feedstock, e.g. DavisonWHPS-12 primary gas oil.

                  TABLE II                                                        ______________________________________                                                          Typical Analysis                                            CHEMICAL ANALYSES Catalyst of Invention                                       SiO.sub.2         58.3                                                        Al.sub.2 O.sub.3  40.1                                                        TiO.sub.2         0.52                                                        Fe.sub.2 O.sub.3  0.43                                                        Na.sub.2 O        0.42                                                        Re.sub.2 O.sub.3  1.29                                                        La.sub.2 O.sub.3  0.74                                                        CeO.sub.2         0.14                                                        Nd.sub.2 O.sub.3  0.31                                                        Pr.sub.6 O.sub.11 0.10                                                        La.sub.2 O.sub.3 /CeO.sub.2 Ratio                                                               5.3                                                         MgO               --                                                          PHASE COMPOSITION                                                             Zeolite Type      USY                                                         Zeolite Lattice K 24.58                                                       Zeolite Content                                                               % Int./Na Y       8.8                                                         Internal Std.     7.7                                                         Nitrogen Method   15                                                          Kaolinite         45                                                                            cc/g                                                        PORE SIZE DISTRIBUTION                                                                          (% of Total Pore Volume)                                    6000 Å        0.03 cc/g (0)%                                              6000-1000 Å   0.09 cc/g (15%)                                             1000-400 Å    0.18 cc/g (31%)                                              400-200 Å    0.12 cc/g (21%)                                              200-100 Å    0.09 cc/g (16%)                                              100-80 Å     0.03 cc/g (5%)                                               80-60 Å      0.03 cc/g (6%)                                               60-20 Å      0.04 cc/g (6%)                                              SURFACE AREA, m2/g                                                                              198                                                         Zeolite Area, m2/g                                                                               99                                                         External Area, m2/g                                                                             108                                                         PORE VOLUME, cc/g                                                             Water P.V. cc/g   0.59                                                        SKELETAL DENSITY, g/cc                                                                          2.57                                                        Apparent Bulk Density g/cc                                                                      0.56                                                        ______________________________________                                    

Though not wishing to be bound by any theory, the acidity provided inthe matrix of the catalyst is believed to more efficiently convert thelarge non-vaporizable and frequently structurally non-accessiblemolecules to zeolite pore dimensions and vaporizable hydrocarbonmolecules of molecular weight which can contact and enter the zeoliteand are thereby converted to compounds in the 38° C.-343° C. (100°F.-650° F.) boiling range (Note FIG. IX). The pore volume and the porevolume distribution is designed to rapidly ingorge and provide broadavenues by which to facilitate access to specific sites for the largehydrocarbon molecules, while the increased pore volume assists indistributing the asphaltenes over a greater portion of the catalyst, thecombination thereby serving to minimize plugging and blocking ofreactant molecules to the zeolite. Also, the high pore volume isintended to speed the departure of smaller molecules before undesirablesecondary reactions occur at the acidic sites. To comprehend theimportance of proper design of pore structure, it should be noted that100 g. of a typical catalyst can contain over 100 million miles oftorturous channels.

Catalyst Zeolite

(Useful references include Zeolite Chemistry and Catalysis, Jule A. Rabo(ACS Monograph 171, copyright 1976) Chapter 4, Lattice Cell Constant andthe aformentioned Davison Z-14 patents.)

Particularly preferred as starting materials for the present inventionare HY zeolites containing rather weak, acidic sites, which produce lowcatalytic coke while demonstrating increased resistance to metalcontamination and high temperature operations. Such zeolites alsoinclude H-Y modifications, such as Davison's Z-14US and LZ-Y72 availablefrom Union Carbide Corporation. The preferred sieves are such asZ-14U.S. and similar sieves with cell constants between 23.30-24.70 Å.Also preferred are NH₄ enchanged Y sieves which convert to HY sievesupon calcination, or in use in the cracking process. The RCC process isespecially suited for use of these zeolites due to the nature of thetwo-stage regenerator. HY zeolites are prepared in many ways such as byDavison's ultra stable technique, pressure exchange, use of F₂ toredistribute aluminum cations and other methods known to yield similarproducts.

It appears probable that the new HY zeolites (which are cheaperrelatively) are to some degree converted in situ in the regenerator,especially the two-stage RCC regenerator, to Ultra Stable Y zeolites(which are much more expensive).

Catalyst Clays

A wide variety of clays may be advantageously employed in the catalystof the present invention and particularly preferred are mixtures of anumber of different clays. Suitable clays include, among others,halloysite, ball clay and Hydrite UF produced by Georgia Kaolin. Huber80B by Huber Co., and Kaowhite and Kaogloss produced by Thiele Company,and naturally occurring kaolinites and boehmites.

The kaolin clay will preferably have crystallites (particles) 80% ofwhich have a size of less than about 2 microns (spherical equivalents),more preferably less than about 1 micron, and most preferably less thanabout 0.5 microns.

The desired percentage composition ranges for clays should preferably befrom about 20 to about 65, more preferably from about 30 to about 60,and most preferably from about 35 to about 50, based on the weight ofthe total catalyst. While not generally appreciated, by a selectivemethod of incorporation, and by selective choice of kaolin clay with ahigh diameter to thickness ratio, preferably 10/1 or greater, utilizedin this catalyst preparation, the clay can be converted into a house ofcards arrangement, so as to achieve the preferred pore structuredescribed herein.

Catalyst Gels

The gels employed in the preparation of the catalysts of the presentinvention are preferably silica-alumina gels e.g. high and low aluminaon silica gels, silica-alumina gels, co-gels and alumina-coated silicagels. These can be produced by techniques known to those skilled in theart, e.g. see U.S. Pat. Nos. 2,951,815 (Craven); 3,034,994 (Braithwaite,McGrew, Hettinger, D'Amico); 3,346,509 (Stewart) and 4,226,743 (Seese)which are incorporated herein by reference.

The percentage of gels will range from about 30 to about 60, morepreferably from about 30 to about 50, and most preferable from about 35to about 45 percent by weight based on the total weight of the catalyst.In particular co-gels are especially preferred as they not only providean acidic matrix of major importance but they also possess anon-crystalline zeolite like character to the gel wherein nickel,vanadium and other metallic contaminants can be trapped.

Co-Gel Matrix

This invention involves the preparation of a heavy hydrocarbon crackingcatalyst which contains an improved matrix binding system so that thecatalyst is thermally and hydrothermally stable and attrition resistantwhen contaminated with high metals. It has been found that theparticular method described here will result in a catalyst which hasacidity not only in the zeolite but also in the matrix binding system.This acidity in the matrix is found to be critical to the efficientcracking of large hydrocarbon molecules found in heavy petroleumfractions. These heavy hydrocarbons may range up to 100 Å in size andcannot be catalytically cracked in the 13 Å cavity of the zeolite asdone with normally light FCC feedstocks. In our catalysts the largeorganic compounds are first cracked at a matrix acidic site into smallermolecules which can then be vaporized and reacted further at the zeolitesites. The matrix is able to crack the heavy petroleum fraction becauseit has a large portion of its pore volume in stable pores in the 100 to1000 Å range and many of the acidic sites are located along these pores.

The pore volume of the final catalyst can be made to fall between 0.2and 0.7 cc/gm without losing its unique attrition properties but we havefound that a pore volume near 0.45-0.55 cc/gm to be particularlydesirable.

Typically, the catalyst prepared by these procedures will contain from20 to 50 percent clay, from 0 to 30 percent alumina in the form of aprecipitate; from 5 to 30 percent zeolite, with the remainingcomposition comprising the silica-alumina co-gel.

It is the alumina phase of the matrix system which is believed toprovide both stabilization to the zeolite and matrix acidic sites whilealso passivating the contaminant metals which prevents their destructionof the zeolite.

Although other hydrogel gel systems have been disclosed, such as U.S.Pat. No. 3,912,619 Maze et al, they do not have the unique combinationof proper pore volume, pore size distribution, attrition resistance andstable acidic-sites of the new co-gel system. Systems which contain analumina phase such as U.S. Pat. Nos. 4,333,857 and 4,253,989 to Lim etal have been disclosed to improve abrasion resistance but they do notpossess the high matrix acidity and proper pore volume distributionobtained with the product of the disclosure.

Broadly, the invention contemplates the use of a catalyst systemproduced from a system wherein sodium silicate and clay is reacted withaluminum sulfate and sodium aluminate at high pH to produce a hydrogel.This hydrogel is further reacted with aluminum sulfate to achieve aslurry with a pH near 4. The pH of the slurry is increased to near 6with ammonium hydroxide to precipitate the soluble aluminum. A zeolitemay be added before or after the alumina precipation step. The slurry isfiltered, washed, spray dried and ion exchanged to form the finalcracking catalyst.

Catalyst Rare Earths

Rare earths useful for the present invention include cerium, lanthanum,neodynium, praesodymium, samarium, but any of the elements generallytermed "rare earths" may be employed advantageously with specialapplications of the invention.

Particularly preferred are ratios of from about 0.5 to about 6, morepreferably from about 1 to 5, and most preferably from about 2 to 4 oflanthanum to cerium and such ratios will generally be present in amountsranging from about 0.50 to 2.0 wt % rare earth oxides, based in totalcatalyst.

Catalyst Pore Volume

Because of the nature of the feedstocks being processed by the catalystof the present invention, the pore volume of the present catalyst hasbeen found to be partially important. The high boiling impurities (e.g.above about 510° C. (about 950° F.)) which are found in relatively highamounts in the heavy crude feedstocks employed with the presentinvention, do not vaporize readily and some such as asphaltenes are notsusceptible to vaporization and are laid down on the catalyst under theconditions of temperature and pressure utilized in the process. Theseheavy materials are therefore laid down on the catalyst and can eitherundergo thermal cracking or catalytic cracking. For catalytic cracking,there must be either acidic sites on the surface of the catalyst matrixor the heavy materials must diffuse through the pore structure of thecatalyst to contact the inner zeolite crystals.

When one contemplates that from 20-50% of reduced crude exists as aliquid at the conditions of the riser, it can be visualized that thisliquid material boiling above 510° C. (950° F.), can cause pore pluggingand can lead to diffusion problems both with regard to the feeddiffusing into the catalyst to contact the acidic sites of the matrixand/or the zeolite, and also the products of cracking diffusing out.Taking these problems into consideration, the present invention employsa pore volume in its catalyst of above about 0.4 cc/gram, morepreferably above about 0.45 cc/gram. This pore volume should principallybe in the matrix of the catalyst. By having a pore volume of 0.45cc/gram, or even greater, and utilizing a catalyst to oil ratio of 6 to14:1, the total volume of catalyst pore volume will be some 3 to 7 timesthe volume of the feed introduced, so that the ability of the feed tocompletely block or substantially restrict a pore will be statisticallyreduced to a very low level.

Water pore volume is determined by the well-known W. R. Grace Method401, water titration test for pore volume.

A second reason for the high pore volume is due to the high metals, e.g.nickel, vanadium and iron, contained in the feeds utilized with thepresent invention which can gradually build up on the outer surface ofthe catalyst, decreasing pore volume and blocking off the acidic matrixfrom contact with fresh feed materials. With the high pore volume of thepresent invention, even with substantial metal coating and blocking, alarge pore volume will remain to provide relatively easy ingress of feedmaterials to the acidic matrix and egress of cracked products from thematrix. When utilizing an acidic matrix, the high pore volume permitsthe feed materials, which may be in the liquid state, to diffuse easilyinto the matrix, and once having cracked, the feed materials, now in thegaseous state, can more readily diffuse for further cracking in thematrix and preferably in the zeolite and also exit rapidly from thematrix.

Related catalysts and processes for their manufacture are discussed inU.S. Ser. No. 06/318,185, filed May 20, 1981 (PCT 00492 filed in theU.S. Receiving Office Apr. 10, 1981 and assigned to Ashland Oil, Inc.and entitled "Large Pore Volume Catalysts for Heavy Oil Conversion").The entire disclosure of that application also being incorporated hereinby reference.

Catalyst Pore Distribution

As previously mentioned, the catalyst pore size distribution isrelatively critical in the catalyst of the present invention forconversion of heavy oils, to facilitate handling of the highly viscousmaterial which is deposited within the pores and to permit it to becracked, and permitting vaporization under the temperatures, andpressures existing in the reaction zone, thereby facilitating transportas a vapor to the zeolite matrix of the catalyst for further cracking.

If pore distribution is too small, one can obtain pore blockage and iftoo large, one obtains only a few pores for admitting feed stock to thematrix.

Therefore, this catalyst emphasizes (in the sense of this catalyst) twothings: there is a critically balanced action between the matrix and thezeolite; within the matrix we have a zeolite catalyst consisting ofzeolite particles as disclosed and which zeolites in this applicationand in other applications by Ashland Oil are of preferred minimum size.By minimum size we mean preferably below one micron and attempting toapproach a tenth of a micron in size or less. Frequently thecrystallites may, by SEM, appear to be even smaller but occurring inclumps. It is also preferred that clumps be dispersed. Thus with thesesmall particles one needs an extensive and optimized pore sizedistribution to ensure an adequate and usable approach for reactantswhich enables the vaporized hydrocarbons to enter the"portal" surfacearea of the zeolite and also to exit the zeolite, thus diminishingdiffusion problems. In the course of our work, catalysts have beenevaluated that have had adequate pore volume but with a pore sizedistribution mainly in the 1,000-6,000Å range being associated with lowsurface area and therefore low acidity content, and these have tended tobe less effective. However, on the other hand, a catalyst, whenincorporating certain materials may have only microporosity, e.g. withpore sizes mainly in the 20-50 or 20-70Å range. This is, on the otherhand, too small of a size because diffusion rates are greatly reducedand are readily blocked by heavy non-vaporized materials. These smallpores are also associated with large surface area and, because of theirsize and associated surface area, retain much carbonaceous material,difficult to remove by stripping, thereby resulting in enhanced coke.The ideal pore size distribution should be in a range of about 100-1000Angstroms, and with additional feeder pores or dual pores which feedinto the pore size in the range of 1000-6,000Å with balanced matrix andzeolite acidity -- the matrix serves to permit access of molecules tothe sieves, protect the sieves, break down large molecules to propersize for sieve cracking, convert slurry oil to LCO or gasoline, andblock the poisoning action of basic nitrogen compounds.

Balanced Acidity

By balanced acidity between the sieve and the matrix, we refer to thatacidity measured by titration with n-butylamine, which value representsthe acidity in both the matrix and the sieve. Titration withtridodecylamine, however, a molecule unable to enter the sieve,represents accessible acidity in the matrix. Therefore acidity in thematrix, after thermal treatment at 149° C. (300° F.) is measured by useof tridodecylamine and acidity in the sieve by n-butylamine titration ofthe sieve alone. Acidity contribution by the sieve then is equal toacidity by n-butylamine, as measured in the absence of matrix times theconcentration in the finished catalyst. The ratio of acidity in thematrix to acidity contributed by the sieve may be expressed as: ##EQU2##

The following Table III presents values for acidity distribution for thecatalyst in this application compared with SDX, a catalyst wellrecognized as being excellent for vacuum gas oil processing.

It can be seen that the SDX catalyst has essentially no acidity in thematrix and thus is unable to catalytically crack extraordinarily largemolecules, as is the catalyst described herein. Note that in the case ofthe catalyst described herein, the ratio of matrix acidity to sieveacidity is 1.0.

                  TABLE III                                                       ______________________________________                                                  n-butylamine                                                                           tridodecyl-                                                                             Ratio                                                      Total Acidity                                                                          amine Ma- Matrix Acidity                                             in the Sieve                                                                           trix Acidity                                                                            Sieve Acidity                                    ______________________________________                                        Catalyst #1 (conv.)                                                                       0.25       0.00      0.00                                         Catalyst of 0.22       0.22      1.00                                         Invention                                                                     Example 1                                                                     ______________________________________                                    

Total acidity is measured after calcining the catalyst at 149° C. (300°F.) for 16 hours in air.

Ion Exchange Properties Related to Metals Tolerance

It has been demonstrated that the catalysts described herein areexceptionally resistant to metals poisoning. While not wishing to beheld to theory, it isproposed that this special matrix, by means ofco-gelling, possesses small ion exchange zones not unlike the ionexchange properties of the old now crystalline synthetic zeolite watersoftener gelsof the 1930's. E.g. the following table shows the resultsof titrating the finished catalyst with n-butylamine and tridodecylamineand compared with the zeolite contained acidity.

                  TABLE IV                                                        ______________________________________                                        Catalyst of Invention Example 1                                               ______________________________________                                        n-butylamine acidity total catalyst                                                                    0.77   meg/gm                                        n-butylamine acidity of contained sieve                                                                0.22   meg/gm                                        tridodecylamine acidity  0.22   meg/gm                                        Total accessible acidity 0.44   meg/gm                                        Total micro porous acidity unaccounted for                                                             0.33   meg/gm                                        and evidently in the matrix                                                   ______________________________________                                    

The results show that the catalyst possesses some 0.33 meg/gm of ionexchangeable acid sites that are neither in the sieve, nor accessible totridodecylamine, but obviously still available for binding orinactivating contaminating metals.

Resistance to Vanadium Poisoning With Lanthanum

Many tests have confirmed that deposition, or precipitation presumablyas rare earth oxide gel, as compared with ion exchange, of lanthanum inthe matrix, is able to reduce the deleterious effect of vanadium. FIG.VII shows the effect of lanthanum in protecting the catalyst fromdeactivation by vanadium.

High Light Cycle Oil/Heavy Cycle Oil Ratio

Previously, when the price of crude oil was much lower, the price ofheavy fuel oil was not far removed from the value of other petroleumfeedstocks and products. Today, however, the value of #6 fuel isconsiderably below the price of crude and refinery products andincluding more valuable light cycle oil which prior to the developmentof this process had to be added to vacuum bottoms distilled from crudeoil, in order to meet viscosity requirements, thereby also depreciatingthe value of light cycle oil which when incorporated into light heatingoil has a much higher value. Because of these economic factors it isdesirable to produce as little slurry oil as possible. Careful study ofthe chemical composition of slurry oil surprisingly showed it to be acombination of mainly polynuclear aromatic molecules, no longersusceptible to cracking, and a second portion highly paraffinic. Basedon this analysis, further major effort was placed in also developing acatalyst able to greatly reduce slurry oil yield by intensifyingappreciably the acidity of the matrix over those catalysts available atthe present time. The results shown in FIG. VI testify to the success ofthis catalyst in meeting this objective. This property alone greatlyincreases the economic value of the product and process.

Balancing Properties

An HY zeolite is well known for its ability to produce a high octaneproduct and low coke. The high octane has been explained as being due tothe inability of HY to transfer hydrogen back to high octane olefinsproduced in the cracking reaction. By the same token, an inability tostrip hydrogen from the feed apparently results in production of lesscoke from butadiene and polynuclear aromatic production. Rare earthexchanged sieves, on the other hand, appear to produce more coke andlower octane number by causing an acceleration of these reactions.

On the other hand, rare earth exchanged zeolites have been demonstratedto be more active, more stable to temperature and steam and moreresistant to metals degradation. We have discovered that a verydelicate, narrow and optimum balance between these extremes, results ina catalyst which possesses the best characteristics of both HY and rareearth exchanged Y sieves. This balance was carefully explored and anoptimum arrived at by many experiments, followed by pilot runs in the200 B/D demonstration unit.

FIGS. X and XI illustrate the effect of varying the rare earth contentof a zeolite in an inorganic oxide matrix. As the rare earth contentincreases catalyst activity and gas-coke mode increases. However,gasoline yield is optimized at 2.5-3.5 wt % rare earth oxides which isapproximately 30-60% of total exchange capacity.

Additional Materials

The process of the present invention may be operated with the abovedescribed carbo-metallic oil and catalyst, and with recycled sour wateras substantially tthe only additional material charged to the reactionzone. But the charging of other additional materials is not excluded.The charging of recycled oil to the reaction zone has already beenmentioned. As described in greater detail below, still other additionalmaterials fulfilling a variety of functions may also be charged.

Added materials may be introduced into the process in any suitablefashion, some examples of which follow. For instance, they may beadmixed with the carbo-metallic oil feedstock prior to contact of thelatter with the catalyst. Alternatively, the added materials may, ifdesired, be admixed with the catalyst prior to contact of the latterwith the feedstock. Separate portions of the added materials may beseparately admixed with both catalyst and carbo-metallic oil. Moreover,the feedstock, catalyst and additional materials may, if desired, bebrought together substantially simultaneously. A portion of the addedmaterials may be mixed with catalyst and/or carbo-metallic oil in any ofthe above described ways, while additional portions are subsequentlybrought into admixture. For example, a portion of the added materialsmay be added to the carbo-metallic oil and/or to the catalyst beforethey reach the reaction zone, while another portion of the addedmaterials is introduced directly into the reaction zone. The addedmaterials may be introduced at a plurality of spaced locations in thereaction zone or along the length thereof, if elongated.

The amount of additional materials which may be present in the feed,catalyst or reaction zone for carrying out the above functions, andothers, may be varied as desired; but said amount will preferably besufficient to substantially heat balance the process. These materialsmay for example be introduced into the reaction zone in a weight ratiorelative to feed of up to about 0.4, preferably in the range of about0.04 to about 0.4, more preferably about 0.04 to about 0.3 and mostpreferably about 0.05 to about 0.25.

The addition of steam to the reaction zone is frequently mentioned inthe literature of fluid catalytic cracking. Addition of liquid water tothe feed is discussed relatively infrequently, compared to theintroduction of steam directly into the reaction zone. However, inaccordance with the present invention it is particularly preferred thatliquid water be brought into intimate admixture with the carbo-metallicoil in a weight ratio of about 0.04 to about0.15 at or prior to the timeof introduction of the oil into the reaction zone, whereby the water(e.g., in the form of liquid water or in the form of steam produced byvaporization ofliquid water in contact with the oil) enters the reactionzone as part of the flow of feedstock which enters such zone. Althoughnot wishing to be bound by any theory, it is believed that the foregoingis advantageous in promoting dispersion of the feedstock. Also, the heatof vaporization of the water, which heat is absorbed from the catalyst,from the feedstock, or from both, causes the water to be a moreefficient heat sink than steam alone. Preferably the weight ratio ofliquid water to feed is about 0.04 to about 0.15, more preferably about0.05 to about 0.10.

Of course, the liquid water may be introduced into the process in theabove described manner or in other ways, and in either event theintroduction of liquid water amd recycled, condensed sour water, may beaccompanied by the introduction of additional amounts of water as steaminto the same or different portions of the reaction zone or into thecatalyst and/or feedstock. For example, the amount of additional steammay be in a weight ratio relative to feed in the range of about 0.01 toabout 0.25, with the weight ratio of total H₂ O (as steam and liquidwater) to feedstock being about 0.3 or less. The charging weight ratioof liquid water relative to steam in such combined use of liquid waterand steam may thus range from about 5 to about 0.1. Such ratio may bemaintained at a predetermined level within such range or varied asnecessary or desired to adjust or maintain the heat balance of thereaction.

Other materials may be added to the reaction zone to perform one or moreof the above described functions. For example, thedehydrogenation-condensation activity of heavy metals may be inhibitedby introducing hydrogen sulfide gas into the reaction zone. Hydrogen maybe made available for hydrogen deficient carbo-metallic oil feedstocksby introducing into the reaction zone, hydrogen gas or a conventionalhydrogen donor diluent such as a heavy naphtha or relatively lowmolecular weight carbon-hydrogen fragment contributors, including forexample: light paraffins; low molecular weight alcohols and othercompounds which permit or favor intermolecular hydrogen transfer; andcompounds that chemically combine to generate hydrogen in the reactionzone such as by reaction of reduced metal with water, reaction of carbonmonoxide with water, or with alcohols, or with olefins, or with othermaterials or mixtures of the foregoing.

All of the above mentioned additional materials (including water) aloneor in conjunction with each other or in conjunction with othermaterials, such as nitrogen or other inert gases, light hydrocarbons,and others, may perform any of the above-described functions for whichthey are suitable, including without limitation, acting as diluents toreduce feed partial pressure and/or as heat sinks to absorb heat presentin the catalyst as received from the regeneration step. The foregoing isa discussion of some of the functions which can be performed bymaterials other than catalyst and carbo-metallic oil feedstockintroduced into the reaction zone, and it should be understood thatother materials may be added or other functions performed withoutdeparting from the spirit of the invention.

Illustrative Apparatus

The invention may be practiced in a wide variety of apparatus. However,the preferred apparatus includes means for rapidly vaporizing as muchfeed as possible and efficiently admixing feed, water and catalyst(although not necessarily in that order), for causing the resultantmixture to flow as a dilute suspension in a progressive flow mode, andfor separating the catalyst from cracked products and any uncracked oronly partially cracked feed at the end of a predetermined residence timeor times, it being preferred that all or at least a substantial portionof the product should be abruptly separated from at least a portion ofthe catalyst.

For example, the apparatus may include, along its elongated reactionchamber, one or more points for introduction of catalyst, one or morepoints for introduction of additional materials including water, one ormore points for withdrawal of products and one or more points forwithdrawal of catalyst. The means for introducing feed, catalyst andother material may range from open pipes to sophisticated jets or spraynozzles, it being preferred to use means capable of breaking up theliquid feed into fine droplets or foam. Preferably, the catalyst, liquidwater (when used) and fresh feed are brought together in an apparatussimilar to that disclosed in U.S. patent application Ser. No. 969,601 ofGeorge D. Myers et al, filed Dec. 14, 1978, the entire disclosure ofwhich is hereby incorporated herein by reference.

It is preferred that the reaction chamber, or at least the major portionthereof, be more nearly vertical than horizontal and have a length todiameter ratio of at least about 10 more preferably about 20 or 25 ormore. Use of a vertical riser type reactor is preferred. If tubular, thereactor can be of uniform diameter throughout or may be provided with acontinuous or step-wise increase in diameter along the reaction path tomaintain or vary the velocity along the flow path.

In general, the charging means (for catalyst, water and feed) and thereactor configuration are such as to provide a relatively high velocityof flow and dilute suspension of catalyst. For example, the vapor orcatalyst velocity in the riser will be usually at least about 25 andmore typically at least about 35 feet per second. This velocity mayrange up to about 55 or about 75 feet per second or higher. The velocitycapabilities of the reactor will in general be sufficient to preventsubstantial build-up of a catalyst bed in the bottom or other portionsof the riser, whereby the catalyst loading in the riser can bemaintained below about 4 or 5 pounds and below about 2 pounds per cubicfoot, respectively, at the upstream (e.g. bottom) and downstream (e.g.top) ends of the riser.

The progressive flow mode involves, for example, flowing of catalyst,feed and steam as a stream in a positively controlled and maintaineddirection established by the elongated nature of the reaction zone. Thisis not to suggest however that there must be strictly linear flow. As iswell known, turbulent flow and "slippage" of catalyst may occur to someextent especially in certain ranges of vapor velocity and some catalystloadings, although it has been reported adviseable to employsufficiently low catalyst loadings to restrict slippage and back-mixing.

Most preferably the reactor is one which abruptly separates asubstantial portion of all of the vaporized cracked products from thecatalyst at one or more points along the riser, and preferably separatessubstantially all of the vaporized cracked products from the catalyst atthe downstream end of the riser. The process of the present inventionuses ballistic separation of catalyst and products; that is, catalyst isprojected in a direction established by the riser tube, and is caused tocontinue its motion in the general direction so established, while theproducts, having lesser momentum, are caused to make an abrupt change ofdirection, resulting in an abrupt, substantially instantaneousseparation of product from catalyst. In a preferred embodiment referredto as a vented riser, the riser tube is provided with a substantiallyunobstructed discharge opening at its downstream end for discharge ofcatalyst. An exit port in the side of the tube adjacent the downstreamend receives the products. The discharge opening communicates with acatalyst flow path which extends to the usual stripper and regenerator,while the exit port communicates with a product flow path which issubstantially or entirely separated from the catalyst flow path andleads to separation means for separating the products from therelatively small portion of catalyst, if any, which manages to gainentry to the product exit port. Examples of a ballistic separationapparatus and technique as above described, are found in U.S. Pat. No.4,066,533 and 4,070,159 to Myers et al, the disclosures of which patentsare hereby incorporated herein by reference to their entireties.

Preferred Operating Conditions

Preferred conditions for operation of the process are described below.Among these are feed, catalyst and reaction temperatures, reaction andfeed pressures, residence time and levels of conversion, coke productionand coke laydown on catalyst.

Feedstock Temperature

In conventional FCC operations with VGO, the feedstock is customarilypreheated, often to temperatures significantly higher than are requiredto make the feed sufficiently fluid for pumping and for introductioninto the reactor. For example, preheat temperatures as high as about371° C. or 427° C. (about 700° F. or 800° F.) have been reported. But inour process as presently practiced it is preferred to restrictpreheating of the feed, so that the feed is capable of absorbing alarger amount of heat from the catalyst while the catalyst raises thefeed to conversion temperature, at the same time minimizing utilizationof external fuels to heat the feedstock. Thus, where the nature of thefeedstock permits, it may be fed at ambient temperature. Heavier stocksmay be fed at preheat temperatures of up to about 316° C. (about 600°F.), typically about 93° C. (about 200° F.) to about 260° C. (about 500°F.), but higher preheat temperatures are not necessarily excluded.

Catalyst Temperature

The catalyst fed to the reactor may vary widely in temperature, forexample from about 482° C. (about 900° F.) to about 871° C. (about 1600°F.), more preferably about 649° C. to about 815° C. (about 1200° F. toabout 1500° F.) and most preferably about 704° C. to about 760° C.(about 1300° F. to about 1400° F.), with about 718° C. to about 746° C.(about 1325° F. to about 1375° F.) being considered optimum at present.

Reactor Temperature

As indicated previously, the conversion of the carbo-metallic oil tolower molecular weight products may be conducted at a temperature ofabout 482° C. (about 900° F.) to about 760° C. (1400° F.), measured atthe reaction chamber outlet. The reaction temperature as measured atsaid outlet is more preferably maintained in the range of about 524° C.to about 704° C. (about 900° F. to about 1200° F.), still morepreferably about 529° C. to about 649° C. (about 925° F. to about 1050°F.) and most preferably about 538° C. to about 621° C. (about 950° F. toabout 1025° F.). Depending upon the temperature selected and theproperties of the feed, a considerable portion of the feed may or maynot vaporize in the riser and must therefore be partially crackedcatalytically so as to achieve vaporization.

Pressure

Although the pressure in the reactor may, as indicated above, range fromabout 10 to about 50 psia, preferred and more preferred pressure rangesare about 15 to about 35 and about 20 to about 35. In general, thepartial (or total) pressure of the feed may be in the range of about 3to about 30, more preferably about 7 to about 25 and most preferablyabout 10 to about 17 psia. The feed partial pressure may be controlledor suppressed by the introduction of gaseous (including vaporous)materials into the reactor, such as for instance the steam, water, andother additional materials described above. The process has for examplebeen operated with the ratio of feed partial pressure relative to totalpressure in the riser in the range of about 0.2 to about 0.8 moretypically about 0.3 to about 0.7 and still more typically about 0.4 toabout 0.6, with the ratio of the partial pressure of added gaseousmaterial (which includes the steam resulting from introduction of H₂ Oto the riser and may also include recycled gases) relative to totalpressure in the riser correspondingly ranging from about 0.8 to about0.2, more typically about 0.7 to about 0.3 and still more typicallyabout 0.6 to about 0.4. In the illustrative operations just described,the ratio of the partial pressure of the added gaseous material relativeto the partial pressure of the feed has been in the range of about 0.25to about 4, more typically about 0.4 to about 2.3 and still moretypically about 0.7 to about 1.7.

Residence Time

Although the residence time of feed and product vapors in the riser maybe in the range of about 0.5 to about 10 seconds, as described above,preferred and more preferred values are about 0.5 to about 6 and about 1to about 4 seconds, with about 0.5 to about 3.0 seconds currently beingconsidered about optimum. For example, the process has been operatedwith a riser vapor residence time of about 2.5 seconds or less byintroduction of copious amounts of gaseous materials into the riser,such amounts being sufficient to provide for example a partial pressureratio of added gaseous materials relative to hydrocarbon feed of about0.8 or more. By way of further illustration, the process has beenoperated with said residence time being about two seconds or less, withthe aforesaid ratio being in the range of about 1 to about 2. Thecombination of low feed partial pressure, very low residence time andballistic separation of products from catalyst are considered especiallybeneficial for the conversion of carbo-metallic oils. Additionalbenefits may be obtained in the foregoing combination when there is asubstantial partial pressure of added gaseous material, especially H₂ O,as described above.

Conversion

In general, the combination of catalyst to oil ratio, temperatures,pressures and residence times should be such as to effect a substantialconversion of the carbo-metallic oil feedstock. It is an advantage ofthe process that very high levels of conversion can be attained in asingle pass; for example the conversion may be in excess of 50% and mayrange to about 90% or higher. Preferably, the aforementioned conditionsare maintained at levels sufficient to maintain conversion levels in therange of about 60 to about 90% and more preferably about 70 to about85%. The foregoing conversion levels are calculated by substracting from100% the percentage obtained by dividing the liquid volume of fresh feedinto 100 times the volume of remaining liquid product which boils at andabove 221° C. (430° F.) (tbp, standard atmospheric pressure).

These substantial levels of conversion may and usually do result inrelatively large yields of coke, such as for example about 5 to about18% by weight based on fresh feed, more commonly about 6 to about 17%and most frequently about 7 to about 16%. The coke yield can more orless quantitatively deposit upon the catalyst. At contemplated catalystto oil ratios, the resultant coke laydown may be in excess of about 0.3,more commonly in excess of about 0.5 and very frequently in excess ofabout 1% of coke by weight, based on the weight of moisture freeregenerated catalyst. Such coke laydown may range as high as about 2%,or about 3%, or even higher.

Catalyst Separation

In certain types of known FCC units, there is a riser which dischargescatalyst and product vapors together into an enlarged chamber, usuallyconsidered to be part of the reactor, in which the catalyst isdisengaged from product and collected. Continued contact of catalyst,uncracked feed (if any) and cracked products in such enlarged chamberresults in an overall catalyst feed contact time appreciably exceedingthe riser tube residence times of the vapors and catalysts. Whenpracticing the process of the present invention with ballisticseparation of catalyst and vapors at the downstream (e.g. upper)extremity of the riser, such as is taught in the above mentioned Myerset al patents, the riser residence time and the catalyst contact timeare substantially the same for a major portion of the feed and productvapors. It is considered advantageous if the vapor riser residence timeand vapor catalyst contact time are substantially the same for at leastabout 80%, more preferably at least about 90% and most preferably atleast about 95% by volume of the total feed and product vapors passingthrough the riser. By denying such vapors continued contact withcatalyst in a catalyst disengagement and collection chamber one mayavoid a tendency toward re-cracking of gasoline and diminishedselectivity.

The abrupt separation of catalyst from product vapors and unconvertedfeed (if any) is also of great assistance. It is for this reason thatthe so-called vented riser apparatus and technique disclosed in U.S.Pat. Nos. 4,070,159 and 4,066,533 to George D. Myers et al is thepreferred type of apparatus for conducting this process. For similarreasons, it is beneficial to reduce insofar as possible the elapsed timebetween separation of catalyst from product vapors and the commencementof stripping. The vented riser and prompt stripping tend to reduce theopportunity for coking of unconverted feed and higher boiling crackedproducts absorbed on the catalyst.

Stripping

In common with conventional FCC operations on VGO, the present processincludes stripping of spent catalyst after disengagement of the catalystfrom product vapors. Persons skilled in the art are acquainted withappropriate stripping agents and conditions for stripping spentcatalyst, but in some cases the present process may require somewhatmore severe conditions than are commonly employed. This may result, forexample, from the use of a carbo-metallic oil having constituents whichdo not volatilize under the conditions prevailing in the reactor, andinstead remain deposited on the catalyst. Such absorbed, unvaporizedmaterial potentially capable of being converted to valuable products isinstead transported to the regenerator, resulting in excessive, lowvalued catalytic coke equivalents. Also, to minimize regenerationtemperatures and demand for regeneration capacity, it may be desirableto intensify conditions of time, temperature and atmosphere in thestripper which are thereby sufficient to reduce potentially volatilehydrocarbon material borne by the stripped catalyst to about 10% or lessby weight of the total carbon loading on the catalyst. Such strippingmay for example include reheating of the catalyst, extensive strippingwith steam, the use of gases having a temperature considered higher thannormal for FCC/VGO operations, such as for instance flue gas from theregenerator, as well as other refinery stream gases such as hydrotreateroff-gas (H₂ S containing), hydrogen and others. For example, thestripper may be operated at a temperature of about 552° C. (about 1025°F.) or higher.

Heat Control

One or a combination of techniques may be utilized in this invention forcontrolling or restricting the amount of regeneration heat transmittedvia catalyst to fresh feed. For example, one may add a combustionpromotor to the cracking catalyst in order to reduce the temperature ofcombustion of coke to carbon dioxide and/or carbon monoxide in theregenerator. Moreover, one may remove heat from the catalyst throughheat exchange means, including for example heat exchangers (e.g. steamcoils) built into the regenerator itself, whereby one may extract heatfrom the catalyst during regeneration. Heat exchangers can be built intocatalyst transfer lines, such as for instance the catalyst return linefrom the regenerator to the reactor, whereby heat may be removed fromthe catalyst after it is regenerated. The amount of heat imparted to thecatalyst in the regenerator may be restricted by reducing the amount ofinsulation on the regenerator to permit some heat loss to thesurrounding atmosphere, especially if feeds of exceedingly high cokingpotential are planned for processing; in general, however, such loss ofheat to the atmosphere is considered economically less desirable thancertain of the other alternatives set forth herein. One may also injectcooling fluids into the regenerator, for example water and/or stream,whereby the amount of inert gas available in the regenerator for heatabsorption and removal is increased.

CO/CO₂ Ratio

Whether practiced with the foregoing techniques or not, the presentinvention includes the technique of controlling or restricting the heattransmitted to fresh feed via recycled regenerated catalyst whilemaintaining a specified ratio between the carbon dioxide and carbonmonoxide formed in the regenerator while such gases are in heat exchangecontact or relationship with catalyst undergoing regeneration. Ingeneral, all or a major portion by weight of the coke present on thecatalyst immediately prior to regeneration is removed in at least onecombustion zone in which the aforesaid ratio is controlled as describedbelow. More particularly, at least the major portion more preferably atleast about 65% and more preferably at least about 80% by weight of thecoke on the catalyst is removed in a combustion zone in which the molarratio of CO₂ to CO is maintained at a level substantially below 5, e.g.about 4 or less. Looking at the CO₂ /CO relationship from the inversestandpoint, it is preferred that the CO/CO₂ molar ratio should be atleast about 0.25 and preferably at least about 0.3 and still morepreferably about 1 or more or even 1.5 or more. While persons skilled inthe art are aware of techniques for inhibiting the burning of CO to CO₂,it has generally been suggested that the mole ratio of CO:CO₂ should bekept less than 0.2 when regenerating catalyst with large heavy metalaccumulations resulting from the processing of carbo-metallic oils; inthis connection see for example U.S. Pat. No. 4,162,213 to Zrinscak, Sr.et al. In this invention however, maximizing CO production whileregenerating catalyst to about 0.1% carbon or less, and preferably about0.05% carbon or less, is a particularly preferred embodiment of thisinvention. Moreover, according to a preferred method of carrying out theinvention the sub-process of regeneration, as a whole, may be carriedout to the above-mentioned low levels of carbon on regenerated catalystwith a deficiency of oxygen; more specifically, the total oxygensupplied to the one or more stages of regeneration can be and preferablyis less than the stoichiometric amount which would be required to burnall hydrogen in the coke to H₂ O and to burn all carbon in the coke toCO₂. If the coke includes other combustibles, the aforementionedstoichiometric amount can be adjusted to include the amount of oxygenrequired.

Still another particularly preferred technique for controlling orrestricting the regeneration heat imparted to fresh feed via recycledcatalyst involves the diversion of a portion of the heat borne byrecycled catalyst to added materials introduced into the reactor, suchas the water, steam, naphtha, other hydrogen donors, flue gases, inertgases, and other gaseous or vaporizable materials which may beintroduced into the reactor.

The larger the amount of coke which must be burned from a given weightof catalyst, the greater the potential for exposing the catalyst toexcessive temperatures. Many otherwise desirable and useful crackingcatalysts are particularly susceptible to deactivation at hightemperatures, and among these are quite a few of the costly molecularsieve or zeolite types of catalyst. FIG. XIII illustrates the improvedhydrothermal properties of the catalyst of this invention as compared toconventional zeolite containing cracking catalysts. The crystalstructures of zeolites and the pore structures of the catalyst carriersgenerally are somewhat susceptible to thermal and/or hydrothermaldegradation. The use of such catalysts in catalytic conversion processesfor carbo-metallic feeds also creates a need for regeneration techniqueswhich will not destroy the catalyst by exposure to highly severetemperatures and steaming. Such need can be met by a multi-stageregeneration process which includes conveying spent catalyst into afirst regeneration zone and introducing oxidizing gas thereto. Theamount of oxidizing gas that enters said first zone and theconcentration of oxygen or oxygen bearing gas therein are sufficient foronly partially effecting the desired conversion of coke on the catalystto carbon oxide gases. The partially regenerated catalyst is thenremoved from the first regeneration zone and is conveyed to a secondregeneration zone. Oxidizing gas is introduced into the secondregeneration zone to provide a higher concentration of oxygen oroxygen-containing gas than in the first zone, to complete the removal ofcarbon to the desired level. The regenerated catalyst may then beremoved from the second zone and recycled to the reactor for contactwith fresh feed. An example of such multi-stage regeneration process isdescribed in U.S. patent application Ser. No. 969,602 of George D. Myerset al, filed Dec. 14, 1978, the entire disclosure of which is herebyincorporated herein by reference. Another example may be found in U.S.Pat No. 4,332,673.

Multi-stage regeneration offers the possibility of combining oxygendeficient regeneration with the control of the CO:CO₂ molar ratio. Thus,about 50% or more, more preferably about 65% to about 95%, and morepreferably about 80% to about 95% by weight of the coke on the catalystimmediately prior to regeneration may be removed in one or more stagesof regeneration in which the molar ratio of CO:CO₂ is controlled in themanner described above. In combination with the foregoing, the last 5%or more, or 10% or more by weight of the coke originally present, up tothe entire amount of coke remaining after the preceding stage or stages,can be removed in a subsequent stage of regeneration in which moreoxygen is present. Such process is susceptible of operation in such amanner that the total flue gas recovered from the entire, completedregeneration operation contains little or no excess oxygen, i.e. on theorder of about 0.2 mole percent or less, or as low as about 0.1 molepercent or less, which is substantially less than the 2 mole percentwhich has been suggested elsewhere. Thus, multi-stage regeneration isparticularly beneficial in that it provides another convenient techniquefor restricting regeneration heat transmitted to fresh feed viaregenerated catalyst and/or reducing the potential for thermaldeactivation, while simultaneously affording an opportunity to reducethe carbon level on regenerated catalyst to those very low percentages(e.g. about 0.1% or less) which particularly enhance catalyst activity.Moreover, where the regeneration conditions, e.g. temperature oratmosphere, are substantially more severe in the second zone than in thefirst zone (e.g. by at least 6° C. (about 10° F.) and preferably atleast about 11° C. (about 20° F.)), that part of the regenerationsequence which involves the most severe conditions is performed whilethere is little or no hydrogen in the coke on the catalyst. Suchoperation may provide some protection of the catalyst from the moresevere conditions. A particularly preferred embodiment of the inventionis two-stage fluidized regeneration at a maximum temperature of at leastabout 6° C. or 11° C. (about 10° F. or 20° F.) higher in the dense phaseof the second stage as compared to the dense phase of the first stage,and with reduction of carbon on catalyst to about 0.05% or less or evenabout 0.025% or less by weight in the second zone. In fact, catalyst canreadily be regenerated to carbon levels as low as 0.01% by thistechnique, even though the carbon on catalyst prior to regeneration isas much as about 1% or greater.

EXAMPLES Example 1 Preparation of a Catalyst of the Invention

1. Into a large tank is added 80.7 kg of sodium silicate. The silicate,containing 28.7 wt. % SiO₂, was mixed with 435 liters of water toachieve a 4.5 wt. % SiO₂ solution.

2. A medium coarse Georgia kaolinite clay in the amount of 46.6 kg isadded with mixing to the dilute silicate solution.

3. In order to form silica-alumina gel, a kg water solution containing16.3 kg of aluminum sulfate hydrate is added to the silicate-claymixture to achieve a pH of approximately 9.5. The resultant slurry washeld at 49° C. (120° F.) for 15 minutes.

4. Next, a water solution containing 9.6 kg of sodium aluminate is addedto the slurry to raise the pH to approximately 12.0 and the resultantslurry was held at 49° C. (120° F.) for 30 minutes.

5. A solution containing 54.2 kg of aluminum sulfate hydrate is added tothe slurry to reduce the pH to approximately 3.5.

6. The pH is then raised to 6.0 with NH₄ OH.

7. A pH 6 water slurry containing 15.4 kg of an ultrastable Y zeolitesuch as USZ-14 is added to the slurry from step 6.

8. The resultant slurry is dewatered to obtain a slurry containing 15wt. % solids before spray drying to produce a microspherical catalyst.

9. The catalyst is reslurried with water, then washed at pH 6 withdilute water solutions containing ammonium ions.

10. The washed catalyst is exchanged at 38° C. (100° F.) with watersolutions of ammonium sulfate before washing again.

11. Finally the catalyst is exchanged with a water solution of mixturedrare earth chlorides at a pH of 5.2 and a temperature of approximately38° C. (approximately 100° F.) before drying at 177° C. (350° F.) for 30minutes.

Example 2 Preparation of Second Catalyst of the Invention

1. Water is mixed with 16 Kg of a ultrastable zeolite such as USZ-14 tomake an approximately 30-40% slurry. A Rare Earth chloride solutioncontaining 0.85 kg of rare earth oxides is added to the zeolite slurry.The resultant zeolite slurry is held at room temperature for use in Step4.

2. Into a large tank is added 80.7 kg of sodium silicate. The silicate,containing 28.7 wt % SiO₂, was mixed with 435 liters of water to achieve4.5 wt % SiO₂ solution.

3. A medium coarse Georgia kaolinite clay in the amount of 46.6 kg isadded with mixing to the dilute silicate solution.

4. A water slurry containing the partially rare earth exchangedultrastable Y zeolite from Step 1 is added with mixing to the slurry ofStep 2.

5. In order to form silica-alumina gel, a water solution containing 16.3kg of aluminum sulfate hydrate is added to the silicate-clay mixture tothe silicate-clay mixture to achieve a pH of approximately 9.5. Theresultant slurry was held at 32° C. (90° F.) for 15 minutes.

6. Next, a water solution containing 9.6 kg of sodium aluminate is addedto the slurry to raise the pH to approximately 12.0 and the resultantslurry was held at 32° C. (90° F.) for 30 minutes.

7. A solution containing 60.0 kg of aluminum sulfate hydrate is added tothe slurry to reduce the pH to approximately 3.5.

8. The pH is then raised to approximately 6.0 with NH₄ OH.

9. The resultant slurry is dewatered to obtain a slurry containing 15 wt% solids before spray drying to produce a microspherical catalyst.

10. The catalyst is reslurried with water, then washed at pH 6 withdilute water solutions containing ammonium ions.

11. The washed catalyst is exchanged at 38° C. (100° F.) with watersolutions of ammonium sulfate before washing again.

12. Finally the catalyst is exchanged with a water solution of mixturedrare earth chlorides with a high La/Ce ratio at a pH of 5 and atemperature of approximately 38° C. (approximately 100° F.) beforedrying at 177° C. (350° F.) for 30 minutes.

Catalyst Performance

Catalysts having the aforementioned characteristics are able to performexceptionally well under severe operating conditions and on poor qualityfeedstocks. Following are results based on experimental runs, on a 200B/D demonstration unit performed on a preferred catalyst (Table VI), ona residual feedstock, possessing the properties shown in Table V, andcompared with several catalysts (Table VI) commercially available,normally used for processing vacuum gas oil. The considerable increasein gasoline and the equally significant reduction in coke and slurry oilat essentially equal conversion is apparent as shown in FIGS. I throughVI.

                  TABLE V                                                         ______________________________________                                        Feeds                                                                                                   735 TANK                                                                      MIXED REDUCED                                       FEED             ABL      CRUDES                                              ______________________________________                                        API Gravity at 16° C. (60° C.)                                                   18.6     18.7                                                Characterization Factor                                                                        11.80    11.54                                               Ramsbottom Carbon, Wt. %                                                                       5.6      6.1                                                 Sulfur Content, Wt. %                                                                          2.68     2.1                                                 Nickel Content, ppm                                                                            10.0     15.0                                                Vanadium Content, ppm                                                                          25.0     75.0                                                Basic Nitrogen, Wt. %                                                                          0.0450   0.0630                                              Iron Content, ppm                                                                              8.0      3.0                                                 Distillation (D-1160)                                                                     (10%)    716° F.                                                                         620° F.                                              (50%)    825° F.                                                                         862° F.                                              (80%)    944° F.                                                                         982° F.                                  ______________________________________                                    

                  TABLE VI                                                        ______________________________________                                        Products                                                                      FEED TYPE        Conventional                                                                             Invention                                         ______________________________________                                        ARABIAN LIGHT                                                                 Catalyst Prep.: Example                                                                        --     --      2    1    1                                                    #1     #2      --   --   --                                  Catalyst Type                                                                 Conversion, vol. %                                                                             77.1   78.6    81.2 77.6 80.0                                Dry Gas FOE      7.4    7.7     8.1   7.6 7.3                                 Propylene, vol. %                                                                              8.4    9.0     8.8   8.0 8.6                                 Propane, vol. %  3.9    5.1     4.3   3.4 3.8                                 Butylenes, vol. %                                                                              8.8    8.7     10.9 10.8 11.1                                Butanes, vol. %  7.7    10.8    8.0   4.7 6.2                                 Gasoline, vol. % 48.0   46.4    51.3 53.9 53.7                                LCO, vol. %      8.4    5.8     8.8  12.1 10.1                                Slurry, vol. %   14.5   15.6    10.0 10.3 9.9                                 Coke, wt. %      13.8   13.9    12.9 11.6 11.9                                 ##STR1##        62     59      63   69   67                                    100                                                                         METALS ON CATALYST                                                            Nickel on Catalyst, ppm                                                                        1100                                                         Vanadium on Catalyst, ppm                                                                      6900                                                         Incremental Sodium on                                                                           0.54                                                        Cat. Wt. %.                                                                   Incremental Iron on Cat., ppm                                                                  1134                                                         ______________________________________                                    

                                      TABLE VII                                   __________________________________________________________________________    Products                                                                                                    FROM 735 TANK                                   FEED TYPE   ARABIAN LIGHT CRUDE (ABL)                                                                       (MIXED REDUCED CRUDES)                          __________________________________________________________________________    Catalyst Prep, Example                                                                    1     CONVENTIONAL                                                                              1    CONVENTIONAL                               Conversion, vol. %                                                                        77.6  77.01       77.4 76.7                                       Dry Gas FOE*                                                                              7.6   7.4         5.8  5.9                                        Propylene, vol. %                                                                         8.0   8.4         8.5  9.6                                        Propane, vol. %                                                                           3.4   3.9         2.6  3.6                                        Butylenes, vol. %                                                                         10.8  8.8         10.6 8.6                                        Butanes, vol. %                                                                           4.7   7.7         4.7  8.0                                        Gasoline, vol. %                                                                          53.9  48.0        54.0 48.1                                       LCO, vol. % 12.1  8.4         13.1 9.3                                        Slurry, vol. %                                                                            10.3  14.5        9.5  14.0                                       Coke, wt. % 11.6  13.8        12.4 13.9                                       LCO/Slurry Oil Ratio                                                                      1.12  0.58        1.38 0.66                                       Volume Gain 10.8  7.1         8.8  7.1                                        Gasoline Sel.                                                                             0.69  0.62        0.70 0.63                                       Conversion, wt. %                                                                         76.8  75.7        76.3 75.2                                       Dry Gas, wt. %                                                                            6.3   6.2         4.9  4.9                                        __________________________________________________________________________     *FOE = Fuel Oil Equivalents, see "R" under "Catalyst Regeneration".      

                  TABLE VIII                                                      ______________________________________                                        735 Tank - Mixed Reduced Crudes                                               FEED TYPE   Invention      CONVENTIONAL                                       CATALYST TYPE                                                                             Catalyst - Example 2                                                                         OX     #2    #1                                    ______________________________________                                        Conversion Vol. %                                                                         81.4           79.4   79.1  78.3                                  Dry Gas     4.0            6.1    5.4   4.2                                   Propylene   2.2            10.7   9.4   9.8                                   Propane     9.6            3.1    2.5   4.1                                   Butylene    11.1           8.7    9.1   9.2                                   Butane      5.6            7.3    6.6   11.0                                  Gasoline - Vol. %                                                                         54.4           48.5   51.0  45.6                                  LCO - Vol. %                                                                              11.5           11.0   10.2  7.9                                   Slurry - Vol. %                                                                           7.2            9.6    10.7  13.8                                  Coke - Wt. %                                                                              15.5           15.4   15.2  15.5                                  LCO/Slurry - Ratio                                                                        1.6            1.15   0.95  0.57                                  Gasoline Selectivity                                                                      67.0           61.1   64.4  58.2                                  ______________________________________                                    

Similarly, correlations based on 200 B/D runs on two different, highlycarbo-metallic reduced crudes with a catalyst (Example 1) of thisinvention and one considered optimum for vacuum gas oil, is shown inTable VII. Again the contrast in yield is quite apparent. It can beappreciated that these differences in yield represent major economicdifferences.

In Table VIII, another catalyst of this invention (Example 2) iscompared to several commercially available catalysts utilized in vacuumgas oil conversion. The catalyst of this invention prepared by Example 2showed increased conversion, higher gasoline yields and selectivities,lower slurry make and a higher LCO/slurry ratio than the conventionalcatalysts.

Example 3 Conversion Unit Run Using the Catalyst of Example 1

When the catalyst prepared according to Example 1 is contacted with thehydrocarbon feed of Table V in a process as described with respect toFIG. 2 of of U.S. Pat. No. 4,341,624 to Myers, the products obtained areas shown in Tables VI and VII. Similar other runs with catalysts resultsin products as shown in Tables VI, VII and VIII.

Modifications:

It should be understood that the invention is not to be limited by theexamples which serve merely to illustrate certain preferred embodimentsof the invention. The invention is susceptible to a wide variety ofmodifications and variations which will be evident to those skilled inthe art upon reading of the present application. The above-mentionedreferences and related applications and the literature cited therein areincorporated herein by reference and many of the techniques taughttherein will be found to be applicable to the invention. For example,conventional catalysts and/or sorbents can be mixed with the catalystsof the invention before they enter the reaction zone.

Sodium aluminate can replace 25 to 75% of the sodium silicate solutionin the catalyst preparation process.

A small amount of rare earth can be added to the USY sieve to enhanceacidity, activity, and metals resistance while controlling coke andC-like activity and reducing the production of hydrogen.

What is claimed is:
 1. A low coke, high octane, high activity, highselectivity, metal tolerant, thermally stable, low slurry oil producingcatalyst for the conversion of hydrocarbons contaminated with highConradson carbon metals to produce lower molecular weight products, saidcatalyst comprising in combination:(a) from about 8 to about 25% byweight of a zeolite comprising a zeolite selected from the groupconsisting of a HY zeolite and an ultrastable HY zeolite having asilica-alumina mole ratio of at least about 5, and having a celldimension of about 24.30 to about 24.70 angstroms; (b) from about 20 toabout 70 wt. % of a clay comprising kaolin, having a crystalline size offrom about 0.5 to about 2 microns; (c) from about 35 to about 70% of anacidic silica-alumina co-gel matrix comprising at least about 13 wt. %alumina; (d) from about 0.1 to about 3 wt. % of rare earths comprisinglanthanum and cerium in a ratio of from about 1 to about 6; (e) fromabout 15 to about 60 wt. % alumina; (f) wherein said zeolite ispartially exchanged with said rare earths from a solution and whereinsaid zeolite is contained in said acidic matrix and wherein rare eartheshave been precipitated onto said matrix;
 2. A catalyst composition asclaimed in claim 1 comprising a pore volume greater than 0.4 cc per gramas determined by water titration.
 3. A catalyst composition as claimedin claim 1 having from about 40 to 70% of all pores in the 100-1000 Ådiameter range and less than 35% of all pores between 20-100 Å asmeasured by mercury porosimetry.
 4. A catalyst composition as claimed inclaim 1 containing at least 10% or more of all pores in the greater than1000 Å range.
 5. A catalyst composition as claimed in claim 1 comprisingfrom about a ratio of 0.5 to 1.5 acidity in the matrix relative to theacidity in the zeolite.
 6. A catalyst as claimed in claim 1 wherein theacidic silica-alumina co-gel matrix has an acidic component which iscomposed of one or more of the materials selected from the groupconsisting of an alumina coated silica gel, designated in the trade aslow or high alumina; acid leached and alumina reprecipitated calcinedkaolin or halloysite; synthetic montmorillonite, designated SMM;magnesium; titanium and zirconium promoted silica gels; and fluoride andphosophate promoted alumina gels.
 7. A catalyst as claimed in claim 1wherein the kaolin consists of a clay having 80% or more of theparticles less than one micron.
 8. A catalyst as claimed in claim 1wherein the zeolite content is between 10 and 25% by weight.
 9. Acatalyst as claimed in claim 1 wherein the zeolite is an ultrastable HYzeolite.
 10. A catalyst as claimed in claim 1 wherein the rare earthcontent is between 0.01 and 3% by weight.
 11. A catalyst as claimed inclaim 1 wherein at least 10% of the alumina is present as alumina gel.12. A catalyst as claimed in claim 1 wherein 10 to 50% of the exchangesites on the HY zeolite or ultra stable HY zeolite are exchanged withrare earth, wherein the ratio of lanthanum to cerium is between 1 and 6.13. A catalyst as claimed in claim 1 wherein 10 to 70% of the catalyston the HY zeolite or ultra stable HY zeolite are exchanged with rareearth, wherein the ratio of lanthanum to cerium is between 3 and
 6. 14.A catalyst as claimed in claim 1 wherein 25 to 75% of the total rareearth in the catalyst is precipitated in the matrix wherein the ratio oflanthanum to cerium is between 1 and
 6. 15. A catalyst composition asclaimed in claim 1 incorporating additional 10% of titania gel as avanadia immobilizer.
 16. A catalyst as claimed in claim 1 wherein 20%colloidal alumina is added in the catalyst during formation for nickelimmobilization.
 17. A catalyst as claimed in claim 1 wherein 1 to 5% ofsilicic acid is added to enhance attrition resistance.
 18. A catalyst asclaimed in claim 1 in which 20% carbon black is added during preparationin order to enhance micro pore structure.
 19. A catalyst as claimed inclaim 1 comprising a pore volume between 0.5 to 0.6 cc per gram.
 20. Aprocess for the preparation of the catalyst of claim 14 comprising incombination, the steps of:(a) adding a sodium silicate solution to abatch tank so as to yeild a concentration of 3 to 6% SiO₂ ; (b)dispersing kaolin clay in water in a concentration of 20 to 60% andcombining with "a" in such proportions as to yield a catalyst containing20 to 70% of kaolin; (c) adding a solution of alum to "b", so as tobring the pH to 8 to 10 and holding at 24° C. to 49° C. (75° F. to 120°F.) for 1/2 hour or more; (d) adding a sodium aluminate solution to "c"so as to raise the pH back to 12; (e) adding alum solution to "d" so asto drop the pH to 3; (f) adding a slurry of NH₄ HY zeolite to "e" so asto produce a final content of 8 to 35% zeolite in the finished catalyst,said HY zeolite to have been exchanged with rare earth to the extent of10-80% of full rare earth capacity; (g) adding NH₃ to this slurry so asto neutralize the alum and return the pH to 6-9 by precipitating aluminagel; (h) dewatering "g" by filtration, homogenizing, adusting viscosity,and spray drying to a desirable particle size; (i) washing said spraydried particles to remove additional sodium and sulfate ions; (j)contacting with additional rare earth solution at a pH of about 5 so asto precipitate rare earth in the matrix; (k) rinsing, dewatering anddrying to a final product.
 21. A process as decribed in claim 20 inwhich the sodium silicate solution additionally comprises sodiumaluminate solution in the catalyst preparation.
 22. A process forcatalyst preparation as described in claim 20 in which the sodiumsilicate solution is neutralized with sulfuric acid.
 23. A process forthe preparation of the catalyst of claim 1 comprising in combination,the steps of:(a) adding a sodium silicate solution to a batch tank so asto yield a concentration of 3 to 6% SiO₂ ; (b) dispersing kaolin clay inwater in a concentration of 20 to 60% and combining with "a" in suchproportions as to yield a catalyst containing 20 to 70% kaolin; (c)adding a solution of alum to "b", so as to being the pH to 8 to 10 andholding at 24° C. to 49° C. (75° F. to 120° F.) for 2/3 hour or more.(d) adding a sodium aluminate solution to "c" so as to raise the pH backto 12; (e) adding alum solution to "d" so as to drop the pH to 3; (f)adding a slurry of ultra stable HY zeolite to "e" so as to produce afinal content of 8 to 35% zeolite in the finished catalyst, said HYzeolite being exchanged with rare earth to the extend of 10-80% of fullrare earth capacity; (g) adding NH₃ to this slurry so as to neutralizethe alum and return the pH to 6-9 by precipitating alumina gel; (h)dewatering "g" by filtration, homogenizing, adjusting viscosity, andspray drying to a desirable particle size; (i) washing said spray driedparticles to remove additional sodium and sulfate ions; (j) contactingwith additional rare earth solution at a pH of about 5 so as toprecipitate rare earth onto the matrix; (k) rinsing, dewatering anddrying to a final product.
 24. A process for the preparation of thecatalyst of claim 14 comprising in combination, the steps of:(a) addinga sodium silicate solution to a batch tank so as to yield aconcentration of 3 to 6% SiO₂ ; (b) dispersing kaolin clay in water in aconcentration of 20 to 60% and combining with "a" in such proportions asto yield a catalyst containing 20 to 70% kaolin; (c) adding a solutionof alum to "b", so as to bring the pH to 8 to 10 and holding at 24° C.to 49° C. (75° F. to 120° F.) for 1/2 hour or more; (d) adding a sodiumaluminate solution to "c" so as to raise the pH back to 12; (e) addingto "d" an acid leached kaolin clay, which has been previously calcined,so as to drop the pH of "d" to 3; (f) adding a slurry of ammonium HYzeolite to "e" so as to produce a final content of 8 to 35% zeolite inthe finished catalyst, said HY zeolite being exchanged with rare earthto the extend of 10-80% of full rare earth capacity; (g) adding NH₃ tothis slurry so as to neutralize the alum and return the pH to 6-9 byprecipitating alumina gel; (h) dewatering "g" by filtration,homogenizing, adjusting viscosity; and spray drying to a desirableparticle size; (i) washing said spray dried particles to removeadditional sodium and sulfate ions; (j) contacting with additional rareearth solution at a pH of about 5 so as to precipitate rare earth ontothe matrix; (k) rinsing, dewatering and drying to a final product.
 25. Aprocess for the preparation of the catalyst of claim 1 comprising incombination, the steps of:(a) adding a sodium silicate solution to abatch tank so as to yeild a concentration of 3 to 6% SiO₂ ; (b)dispersing kaolin clay in water in a concentration of 20 to 60% andcombining with "a" in such proportions as to yield a catalyst containing20 to 70% kaolin; (c) adding a solution of alum to "b", so as to bringthe pH to 8 to 10 and holding at 24° C. to 49° C. (75° F. to 120° F.)for 1/2 hour or more; (d) adding a sodium aluminate solution to "c" soas to raise the pH back to 12; (e) adding a reaction product of sulfuricacid with calcined kaolin or halloysite to "d" so as to drop the pH to3; (f) adding a slurry of partially rare earth exchanged ammonium HYzeolite to "e" so as to produce a final content of 8 to 35% by weightzeolite in the finished catalyst, wherein said rare earth is exchange tothe extent of 10-80% of available exchange capacity; (g) adding NH₃ tothis slurry so as to neutralize the alum and return the pH to 6-9 byprecipitating alumina gel; (h) dewatering "h" by filtration,homogenizing, adjusting viscosity, and spray drying to a desirableparticle size; (i) washing said spray dried particles to removeadditional sodium and sulfate ions; (j) contacting with additional rareearth solution at a pH of about 5 so as to precipitate rare earth ontothe matrix; (k) rinsing, dewatering and drying to a final product. 26.The process of claim 20 in which the ammonium zeolite of "f" wasobtained as a reaction product of the following sequence: washing asodium Y zeolite with an ammonium ion solution to remove about 30 toabout 60% of all sodium ions and treating the ammonium exchanged zeolitewith a solution of rare earth chloride in a pressure reaction vessel forone to five hours at a temperature between about 121° C. to 232° C.(250° F. to 450° F.) so as to prepare an HY zeolite in which rare earthion is caused to replace sodium in the sodalite cage of the ammonium Yzeolite.
 27. A process for the preparation of the catalyst of claim 1comprising in combination, the steps of:(a) adding a sodium silicatesolution to a batch tank so as to yield a concentration of 3 to 6% SiO₂; (b) dispersing kaolin clay in water in a concentration of 20 to 60%and combining with "a" in such proportions as to yield a catalystcontaining 20 to 70% kaolin; (c) adding a solution of alum to "b", so asto bring the pH to 8 to 10 and holding at 24° C. to 49° C. (75° F. to120° F.) for 1/2 hour or more; (d) adding a sodium aluminate solution to"c" so as to raise the pH back to 12; (e) adding alum solution to "d" soas to drop the pH to 3; (f) adding a slurry of partially rare earthexhanged ammonium HY zeolite to "e" so as to produce a final content of8 to 35% by weight zeolite in the finished catalyst, wherein said rareearth is exchange to the extent of 10-80% of available exchangecapacity; (g) adding NH₃ to this slurry so as to neutralize the alum andreturn the pH to 6-9 by precipitating alumina gel; (h) dewatering "g" byfiltration, homogenizing, adjusting viscosity, and spray drying to adesirable particle size; (i) washing said spray dried particles toremove additional sodium and sulfate ions; (j) contacting withadditional rare earth solution at a pH of about 5 so as to precipitaterare earth onto the matrix; (k) rinsing, dewatering and drying to afinal product.
 28. A process as claimed in claim 20 in which said HYzeolite has been exchanged with rare earth to the extent to 30-60% fullrare earth capacity.
 29. A catalyst composition as described in claim 11in which the alumina gel is present as pseudoboehmite.
 30. A process asdescribed in claim 20 wherein each step in the process occurs in a batchtank in batch operations.
 31. A process as described in claim 20 whereineach step in the process is carried out continuously from one tank toanother so as to result in a continuous flow system.